WO2019152712A1

WO2019152712A1 - Waterborne compositions for forming uniformly-textured surfaces, and applications thereof

Info

Publication number: WO2019152712A1
Application number: PCT/US2019/016149
Authority: WO
Inventors: Gurminder Kaur Paink; Philseok Kim; Grant William Tremelling; Tehila NAHUM
Original assignee: Adaptive Surface Technologies, Inc.
Priority date: 2018-01-31
Filing date: 2019-01-31
Publication date: 2019-08-08

Abstract

In various aspects, coating compositions are provided for creating high-quality uniformly textured surfaces on the food- or drug-contacting surfaces of containers and the like. The coating compositions can include components that are generally recognized as safe for food and drug packaging. Surfaces are provided formed from the compositions, and methods of making the compositions and methods of making surfaces using the composition are also provided. The surfaces can stably support a lubricating liquid to create a slipper surface in the food and drug packaging. In some aspects, the lubricating liquid can be an edible oil. The coating compositions and methods are suitable for use with the low surface energy polymers commonly found in food and drug packaging. Examples of such polymers can include polypropylene and polyethylene homopolymers and copolymers.

Description

WATERBORNE COMPOSITIONS FOR FORMING UNIFORMLY-TEXTURED SURFACES,

AND APPLICATIONS THEREOF

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to, and the benefit of, co-pending U.S. provisional application entitled “WATERBORNE COMPOSITIONS FOR FORMING UNIFORMLY- TEXTURED SURFACES, AND APPLICATIONS THEREOF” having serial no. 62/624,761 , filed January 31 , 2018, the contents of which are incorporated by reference in their entirety.

TECHNICAL FIELD

[0002] The present disclosure generally relates to coatings and surfaces, and in particular to coatings and surfaces for the food and drug industry.

BACKGROUND

[0003] Several solutions have been developed for creating slippery coatings and surfaces. However, creating slippery coatings on certain types of surfaces remains challenging. In particular, for food packaging and drug packaging applications, a number of problems immediately arise. The coating compositions need to be safe for food and drug packaging applications. Also, because of the types of materials commonly found in food and drug packaging, creating high-quality coatings in food and drug packaging poses additional challenges related to the coating quality and the wetting of the composition on the substrate. These challenges are described more fully in the detailed description below.

[0004] There remains a need for improved coating compositions for food and drug packaging as well as coatings and coated articles formed therefrom that overcome the aforementioned deficiencies.

SUMMARY

[0005] A number of solutions are provided that overcome one or more of the aforementioned problems. In various aspects, this disclosure is directed to waterborne coating compositions for forming food-safe coatings or drug-safe coatings on low surface energy substrates such as PP, TPO, and HDPE. The coating compositions can be used to create coatings on low surface energy substrates, and in particular high-quality coatings that are uniformly-textured or substantially uniformly-textured. The coatings can support a lubricating liquid such that the lubricating liquid wets and stably adheres to the substrate to form a slippery surface repelling food, drug, and/or foulants.

[0006] In one or more aspects, a surface is provided for food or dug packaging, the surface including a low surface energy substrate having a first low-energy surface; and a base coat layer stably adhered to and coating at least a portion of the first low-energy surface. In various aspects of the disclosure, the base coat layer has about 40 parts by weight to about 60 parts by weight of a low surface energy polymer having a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter; about 37 parts by weight to about 50 parts by weight of nanoparticles; and an outer surface opposite to the first low-energy surface, the outer surface having a substantially uniformly-textured outer surface. The outer surface can have an oil spontaneously wetting and adhering to the outer surface of the base coat layer to form a slippery liquid overlayer. In various aspects, the oil is safe for food and drug packaging. In some aspects, the oil is a component that is generally recognized as safe. In still further aspects, the oil is an edible oil.

[0007] The base coat layer can be of a very high quality, even when applied to low surface energy substrates that are difficult to coat. In various aspects of the disclosure, the base coat layer is substantially free of cracks. In some aspects, the outer surface of the base coat layer has a water contact angle of about 100 to about 140 In some aspects, the outer surface of the base coat layer is substantially free of agglomerates of the nanoparticles. This can create a substantially uniformly textured substrate. The substantially uniformly-textured outer surface, in some aspects, has a nanoscale texturing. The substantially uniformly-textured outer surface is, in some aspects, free of macroscale texturing. In some aspects, the base coat layer, when dried, has an average film thickness perpendicular to the first low-energy surface of about 5 microns to about 30 microns. In various aspects, the base coat layer is not a superhydrophobic surface. In some aspects of the disclosure, the base coat layer has a mass fraction ( y ) of about 0.25 to about 0.50 or about 0.35 to about 0 45

[0008] The surface can be created from a variety of coating compositions. In some aspects, the coating composition includes about 6 parts by weight to about 10 parts by weight of a low surface energy polymer based upon a total weight of the coating composition; about 5 parts by weight to about 9 parts by weight of nanoparticles based upon the total weight of the coating composition; about 1 part by weight or less of a volatile base based upon the total weight of the coating composition; and about 74 parts by weight to about 87 parts by weight water based upon the total weight of the coating composition. In some aspects, the low surface energy polymer has a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter.

[0009] In some aspects, the coating composition is sprayable. In some aspects, when the composition is sprayed onto a first low-energy surface of a low surface energy substrate and annealed, the composition forms a base layer stably adhered to the first low-energy surface. In some aspects, when the composition is sprayed onto a first low-energy surface of a low surface energy substrate, the composition wets the first low-energy surface prior to drying. In some aspects, the base layer after annealing has an outer surface opposite to the first low-energy surface, the outer surface being a substantially uniformly-textured outer surface.

[0010] Methods of making the coating compositions are also provided. In some aspects, the methods include adding hydrophilic nanoparticles to water and adjusting the pH with a volatile base to form a nanoparticle dispersion; adding the nanoparticle dispersion to an aqueous dispersion of a low surface energy polymer having a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter to form the coating composition. In some aspects, the methods include adding hydrophilic nanoparticles to water and adjusting the pH with a volatile base to form a nanoparticle dispersion; heating the nanoparticle dispersion to a first elevated temperature; adding an aqueous dispersion of a low surface energy polymer to the heated nanoparticle dispersion with stirring to form the coating composition, wherein the low surface energy polymer has a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter. In some aspects, the methods include dispersing hydrophilic nanoparticles in water under high shear to form a nanoparticle dispersion; combining a mineral oil/water dispersion with an aqueous dispersion of a low surface energy polymer to form a polymer dispersion, wherein the low surface energy polymer has a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter; and combining the nanoparticle dispersion and the polymer dispersion under high shear and, if needed, adjusting the viscosity by adding additional water, to form the coating composition. In some aspects, the first elevated temperature is about 75°C to about 1 10°C, about 80°C to about 1 10°C, about 80°C to about 100°C, about 75°C to about 95°C, or about 85°C to about 95°C.

[0011] The pH of the coating composition is, in some aspects, about 9 to about 11.5, about 9 to about 9.5, about 9.5 to about 10, about 10 to about 10.5, about 10.5 to about 1 1 , or about 11 to about 11.5. In some aspects, the hydrophilic nanoparticles are titanium dioxide nanoparticles having an average diameter of about 10 nm to about 50 nm and a uniform particle distribution. In some aspects, the volatile base is ammonium hydroxide.

[0012] Methods of making the base coat layers on a low-energy surface of a substrate are also provided. The methods can include spraying a coating composition provided herein onto the low- energy surface. The methods can also include annealing the coating composition on the low- energy surface at a first elevated temperature for a first period of time to form a base coat layer.

[0013] The surfaces can be formed on a variety of low surface energy substrates. In some aspects, the substrate has a surface energy density of about 25 millinewtons per meter to about 40 millinewtons per meter, or about 25 millinewtons per meter to about 35 millinewtons per meter. In some aspects, the substrate is a high density polyethylene (HDPE) substrate, a low density polyethylene (LDPE) substrate, a polyethylene terephthalate (PET) substrate, a polypropylene (PP) substrate, a polystyrene (PS) substrate, a polyvinyl chloride (PVC) substrate, a polycarbonate (PC) substrate, or a blend or copolymer thereof. In various aspects, the substrate is selected from PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PP bottles and containers, PVC sheets and bags, and LDPE sheets and bags.

[0014] In some aspects, the volatile base can be ammonium hydroxide, dimethylaminoethanol, or a combination thereof. In some aspects, the low surface energy polymer is a polyolefin homopolymer or copolymer. In some aspects, the low surface energy polymer is polyethylene, polypropylene, or a copolymer thereof. In various aspects, the nanoparticles are titanium dioxide, colloidal nanoparticle dispersions, carbon nanoparticles, hydrophilic clay nanoparticles, or a combination thereof. The nanoparticles can by hydrophobic nanoparticles. The nanoparticles can have an average diameter of about 10 nm to about 200 nm and a narrow particle size distribution. In some aspects, the average diameter is about 10 nm to about 100 nm, or about 10 nm to about 50 nm. The base coat layers, forming a substantially uniformly-textured outer surface, can be coated with a variety of lubricating liquids. In some aspects, slippery surfaces can be made by applying an oil to an outer surface of the base coat layer, wherein the oil spontaneously wets and adheres to the outer surface of the base coat layer to form a slippery liquid overlayer. In various aspects, the oil includes medium chain triglycerides, vegetable oil, soybean oil, canola oil, rapeseed oil, corn oil, sunflower oil, high oleic sunflower oil, coconut oil, safflower oil, peanut oil, palm oil, super olein oil, cottonseed oil, ground nut oil, olive oil, rice bran oil, safflower oil, grapeseed oil, walnut oil, flaxseed oil, macadamia nut oil, food/drug grade mineral oil, jojoba oil, algal oil, camelina oil, squalene oil, rice bran oil, juniperberry oil, patchouli oil, amyris oil, styrax oil, or a combination thereof.

[0015] Other systems, methods, features, and advantages of the coating compositions and surfaces and methods of making and using thereof will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Further aspects of the present disclosure will be readily appreciated upon review of the detailed description of its various embodiments, described below, when taken in conjunction with the accompanying drawings.

[0017] FIG. 1 presents schematic diagrams of a side cross-sectional view of (left) a coating under loaded with particles such that the majority of the surface is binder, (center) a coating over-loaded with particles such that the particles are simply resting on the surface and can be brushed off easily, and (right) a good balance between the amount of binder and particles such that the particles are exposed at the surface but still remain trapped inside and/or within the matrix.

[0018] FIG. 2 presents schematic diagrams of a side cross-sectional view of a lubricated surface where (going from left to right) (a) there are insufficient particles in the formulation to create the surface texturing required to immobilize the lubricant; (b) there are a slightly increased particle loading where the lubricant is partially immobilized and the fouling agent can slide but over time will displace the lubricant, (c) a particle loading such that a stable lubricant layer is present that can completely repel the fouling agent, and (d) an over-loaded system that presents pinning points where the fouling agent can adhere to the particles extruding out of the lubricant layer. When the particle loading is such that a slippery liquid-infused porous surface at a thickness such that only lubricating liquid forms the surface above the functionalized, roughened surface (i.e., a smooth liquid interface is presented to the environment), the surface can completely repel the fouling agent. In the case where the particles are hydrophilic, the correct particle loading is when the binder is able to wrap the particles such that there is no longer any dynamic wetting present on the surface.

[0019] FIG. 3 presents schematic diagrams of a side cross-sectional view of an embodiment of a functionalized, roughened surface of the present teachings showing that a bulk coating (left), which contains particles embedded inside the matrix, can present a new surface containing the desired particles and porosity at the surface after exposing the coating to mechanical abrasion (right).

[0020] FIG. 4 is a series of scanning electron microscope (SEM) images of surfaces from Example 1 with particle:binder loading of 0.15 (top) and 0.20 (bottom) at increasing levels of magnification moving from left to right. Even though the surface properties are good in terms of repellency the surface presents many cracks due to poor film cohesion between the binder and the hydrophobic silica particles.

[0021] FIG. 5 is a series of scanning electron microscope (SEM) images of surfaces from Example 1 with increasing isopropanol:ethanol (vol./vol.) ratio moving (form left to right) from 0:20, 5: 15, 10:10, 15:5, 20:0 with increasing levels of magnification from top to bottom. Without the use of the correct co-solvents the system presents cracks and aggregated materials.

[0022] . FIG. 6 is a series of scanning electron microscope (SEM) images of surfaces from Example 1 with increasing isopropanol:methanol (vol./vol.) ratio moving (form left to right) from 0:20, 5: 15, 10: 10, 15:5, 20:0 with increasing levels of magnification from top to bottom.

[0023] FIG. 7 is a series of scanning electron microscope (SEM) images of surfaces from Example 2 with decreasing the temperature for the dispersion of carnauba wax powder in acetone (left to right) and with higher (top) and lower (bottom) levels of magnification.

[0024] FIG. 8 is a series of scanning electron microscope (SEM) images of surfaces from Example 2 with decreasing the ratio of particles to carnauba wax powder to improve film quality (from left to right) and with increasing levels of magnification (from top to bottom).

[0025] FIG. 9 is a series of scanning electron microscope (SEM) images of surfaces from Example 2 with a fixed amount of carnauba wax powder and acetone while decreasing the ratio of particles to polyolefin to improve film quality (from left to right) and with increasing levels of magnification (from top to bottom).

[0026] FIG. 10 is a series of scanning electron microscope (SEM) images of surfaces from Example 2 with increasing amounts of polyolefin to improve film quality (from left to right) and with increasing levels of magnification (from top to bottom).

[0027] FIG. 11 is a series of scanning electron microscope (SEM) images of surfaces from Example 2 with decreasing levels of carnauba wax: polyolefin dispersion ratio (left to right) and with higher (top) and lower (bottom) levels of magnification. [0028] FIG. 12 is a flow diagram depicting the method from Example 4 for forming the coating compositions.

[0029] FIG. 13 is a series of scanning electron microscope (SEM) images of surfaces from Example 4 with increasing mineral oil content added to the polyolefin (from left to right), going from 0 wt% to 2.125 wt%. This experiment is done in the absence of particles.

[0030] FIG. 14 is a series of scanning electron microscope (SEM) images of surfaces from Example 4 as a function of increasing oil content (from left to right) going from 0 wt% to 2.125 wt% for low viscosity mineral oil (top row), high viscosity mineral oil (middle row), and low viscosity synthetic oil (bottom row). The percent recrystallization from differential scanning calorimetry for each film is depicted in the inset.

[0031] FIG. 15 is a series of scanning electron microscope (SEM) images of surfaces from Example 4 as a function of increasing ratio of particle to binder (w/w/) from 0.375 to 0.475 (moving from left to right) and with increasing levels of magnification (from top to bottom). The results of water pinning and water contact angle measurements are also described for each surface.

[0032] FIG. 16A is a series of scanning electron microscope (SEM) images of surfaces from Example 4 as a function of reducing the amount of additional water (wt %) from 70 wt% to 30 wt% showing the reduced sagging during application and improved surface quality. FIG. 16B is a bar graph of the measured water contact angle (degrees) as a function of reducing the amount of additional water (wt %) from 70 wt% to 30 wt% (from left to right). FIG. 16C is a summary chart of the observed dispersion quality, spray quality, and morphology as a function of reducing the amount of additional water (wt %) from 70 wt% to 30 wt%.

[0033] FIG. 17 is a series of scanning electron microscope (SEM) images of surfaces from Example 4 showing the quality of surfaces prepared immediately (left), 1 hour (center), and 24 hours (right) after forming the coating composition, demonstrating shelf stability.

[0034] FIG. 18 is a figure depicting the surfaces prepared from Example 4 as a function of the increasing mixing time (left to right) in minutes and the increasing film thickness (top to bottom) in microns.

[0035] FIG. 19 is a series of scanning electron microscope (SEM) images of surfaces from Example 4 as a function of the increasing mixing time (left to right) in minutes and the increasing film thickness (top to bottom) in microns. [0036] FIG. 20 is a figure depicting the surfaces prepared from Example 4 without (left) and with (right) mechanical defoaming and with increasing thickness from 12 microns (top) to 24 microns (bottom).

[0037] FIG. 21 is a series of scanning electron microscope (SEM) images of surfaces from Example 4 for surfaces prepared without (left) and with (right) mechanical defoaming and with increasing thickness from 12 microns (top) to 24 microns (bottom).

[0038] FIG. 22A is a series of bar graphs of the percentage of lubricant loss for surfaces from Example 4 prepared with and without defoaming as a function of the speed (RPM) and for up to day 3 after formation. FIG. 22B is a series of bar graphs for the water droplet spead on surfaces from Example 4 prepared with and without defoaming. FIG. 22C is a series of graphs of the water droplet speed on surfaces from Example 4 prepared with and without defoaming.

[0039] FIG. 23 is a series of scanning electron microscope (SEM) images of surfaces from Example 4 as function of increasing paraffin wax:mineral oil loading (from left to right) and for increasing levels of magnification (from top to bottom). The results of water pinning and water contact angle measurements are also described for each surface.

[0040] FIG. 24 is a series of scanning electron microscope (SEM) images of surfaces from Example 4 as function of increasing paraffin wax:mineral oil loading (from left to right) and for increasing levels of magnification (from top to bottom). The results of water pinning and water contact angle measurements are also described for each surface.

[0041] FIG. 25 is a series of scanning electron microscope (SEM) images of surfaces from Example 5 as a function of increasing ammonium hydroxide loading (from left to right) and for increasing levels of magnification (from top to bottom).

[0042] FIG. 26 is a graph of the pH versus the ratio of titanium dioxide to ammonium hydroxide.

[0043] FIG. 27A is a series of scanning electron microscope (SEM) images at low magnification of surfaces from Example 5 as a function of decreasing particle:binder loading (from left to right) and for increasing levels of ammonium hydroxide (from top to bottom). FIG. 27B is a series of scanning electron microscope (SEM) images at high magnification of surfaces from Example 5 as s function of decreasing particle:binder loading (from left to right) and for increasing levels of ammonium hydroxide (from top to bottom).

[0044] FIG. 28 is a summary chart of the observations of sagging, crack formation, and settling for the surfaces of Example 5. [0045] FIG. 29 is a chart of the dynamic wetting behavior (both dry and lubricated) and the water droplet racing speed for surfaces from Example 5 as compared to the surfaces of Example 4.

[0046] FIG. 30 is a series of optical microscrope images of surfaces from Example 5 as a function of increasing coating thickness (from left to right).

[0047] FIG. 31 is a series of scanning electron microscope (SEM) images of surfaces from Example 5 as a function of the increased additional water concentration (top to bottom) and for immediate annealing (left) and drying residual water from the system prior to annealing (right).

[0048] FIG. 32 is a series of scanning electron microscope (SEM) images of surfaces from Example 5 demonstrates the effects of added additional water concentration to the system such that it improves film quality but also increases sagging during application.

[0049] FIG. 33 is a series of scanning electron microscope (SEM) images of surfaces from Example 5 of the neat polyolefin dispersion as a function of increasing processing temperature (from left to right) and for increasing levels of magnification (from top to bottom).

DETAILED DESCRIPTION

[0050] A variety of materials and solutions have been developed for creating slippery coatings and surfaces. However, creating slippery coatings on certain types of surfaces remains challenging. For a coating to be useful it must achieve suitable adhesion to the substrate surface. The adhesion and quality of coatings on a surface depend largely upon surface phenomena— the coating composition must flow out on and appropriately interact with the surface of the substrate to be coated. The coating composition should preferably be able to make intimate contact with the surface of the substrate. Such intimate contact is called“wetting” or“wetting out” the surface, and refers to the coating compositions ability to spread over the surface of the substrate.

[0051] For food packaging and drug packaging applications, a number of problems immediately arise. First, coating compositions need to be safe for food or drug packaging. Second, the most common materials used for food and drug packaging are low surface energy substrates, which creates several challenges for coating. Surface energy can be thought of as the excess energy that exists at a surface (as opposed to the bulk) of a solid; this excess energy exists because molecules at the surface cannot interact with as many like neighbors as molecules in the bulk are able to do; therefore, i.e. the surface molecules have excess interaction energy. Substrates such as thermoplastic polyolefin (TPO), polypropylene (PP) and high density polyethylene (HDPE) have low surface energy and therefore may resist being wetted by a coating composition. Overall poor wetting of the coating composition leads to imperfections and low-quality coatings. When forming a slippery liquid infused surface, these imperfections can result in poor wetting of a lubricant on the surface and/or result in pinning points where the food, drug, or a fouling agent can adhere to the imperfections in the surface if they are extruding out of the lubricant layer. Thirdly, creating a slippery liquid-infused surface creates a number of additional limitations on the compatibility of the coating composition and the lubricant, etc., and this becomes even more challenging when limited to only components that are edible or are otherwise safe for food or drug packaging.

[0052] In various aspects, this disclosure is directed to solutions to one or more of these problems. This disclosure describes waterborne coating compositions for forming food-safe coatings and/or drug-safe coatings on low surface energy substrates such as PP, TPO, and HDPE. The coating compositions can be used to create coatings on low surface energy substrates, and in particular high-quality coatings that are uniformly-textured or substantially uniformly-textured. The coatings are capable of supporting lubricating liquid overlayers that wet and stably adhere to the coating layer to form slippery liquid-infused surfaces using lubricants that are safe for food or drug packaging.

[0053] Before the present disclosure is described in greater detail, it is to be understood that this disclosure is not limited to particular embodiments described, and as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. The skilled artisan will recognize many variants and adaptations of the embodiments described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein.

[0054] All publications and patents cited in this specification are cited to disclose and describe the methods and/or materials in connection with which the publications are cited. All such publications and patents are herein incorporated by references as if each individual publication or patent were specifically and individually indicated to be incorporated by reference. Such incorporation by reference is expressly limited to the methods and/or materials described in the cited publications and patents and does not extend to any lexicographical definitions from the cited publications and patents. Any lexicographical definition in the publications and patents cited that is not also expressly repeated in the instant specification should not be treated as such and should not be read as defining any terms appearing in the accompanying claims. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present disclosure is not entitled to antedate such publication by virtue of prior disclosure. Further, the dates of publication provided could be different from the actual publication dates that may need to be independently confirmed.

[0055] Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure, the preferred methods and materials are now described. Functions or constructions well-known in the art may not be described in detail for brevity and/or clarity. Embodiments of the present disclosure will employ, unless otherwise indicated, techniques of nanotechnology, organic chemistry, material science and engineering and the like, which are within the skill of the art. Such techniques are explained fully in the literature.

[0056] It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a numerical range of“about 0.1 % to about 5%” should be interpreted to include not only the explicitly recited values of about 0.1 % to about 5%, but also include individual values (e.g., 1 %, 2%, 3%, and 4%) and the sub-ranges {e.g., 0.5%, 1.1 %, 2.2%, 3.3%, and 4.4%) within the indicated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure, e.g. the phrase“x to y” includes the range from‘x’ to‘y’ as well as the range greater than‘x’ and less than‘y’ . The range can also be expressed as an upper limit, e.g.‘about x, y, z, or less’ and should be interpreted to include the specific ranges of‘about x’,‘about y’, and‘about z’ as well as the ranges of ‘less than x’, less than y’, and‘less than z’. Likewise, the phrase‘about x, y, z, or greater’ should be interpreted to include the specific ranges of ‘about x’,‘about y’, and‘about z’ as well as the ranges of ‘greater than x’, greater than y’, and ‘greater than z’. In some embodiments, the term“about” can include traditional rounding according to significant figures of the numerical value. In addition, the phrase“about‘x’ to‘y’”, where‘x’ and‘y’ are numerical values, includes“about‘x’ to about‘y’”. Definitions

[0057] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0058] The articles“a” and“an,” as used herein, mean one or more when applied to any feature in embodiments of the present invention described in the specification and claims. The use of“a” and“an” does not limit the meaning to a single feature unless such a limit is specifically stated. The article“the” preceding singular or plural nouns or noun phrases denotes a particular specified feature or particular specified features and may have a singular or plural connotation depending upon the context in which it is used.

[0059] Throughout the application, where language such as having, including, or comprising is used to describe specific components or process steps, it is contemplated that other aspects exist that consist essentially of, or consist of the specific components or process steps.

[0060] The term "food and drug packaging," as used herein, refers to anything used to contain a food or drug item, and in particular for shipping from a point of manufacture to a consumer, and for subsequent storage and use by a consumer. Food and drug packaging can be made of metal or non- metal, for example, glass, plastic, or laminate, and be in any form. An example of a suitable food and drug packaging can include a plastic bottle, a laminate tube, or a metal can. The food and drug packaging can include a packaging plastic such as polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), and copolymers thereof, or blends thereof, including copolymers and blends with other polymers. Food and drug packaging plastics may also include one or more additives such as fillers, plasticizers, or stabilizers. Food and drug packaging can include PET or HDPE containers or bottles, as well as PVC or LDPE sheets or bags. The food and drug packaging can also include glass bottles or jars. The food and drug packaging can refer to disposable packaging which should be understood as something that is sealed so as to keep its contents free from deterioration until shortly after being opened by a consumer. The manufacturer will often identify the length of time during which the food or drug will be free from spoilage, which typically ranges from several months to years. Thus, a "disposable food and drug packaging" is distinguished from a reusable food and drug packaging such as a storage container or bakeware in which a consumer might make and/or store food for a short period of time. As used herein, the term“shelf life” refers to the period of time that a food/drug product remains saleable to retail customers and remains fit and safe for use or consumption. Changes including, but not limited to, oxidation, odor development, discoloration in addition to microbial changes can alter the shelf life of the food or drug product.

[0061] The articles described herein will often have one or more food-contacting or drug contacting surfaces. For example, food and drug packaging will generally contain one or more food-contacting or drug-contacting surfaces such as the inside surfaces of a bottle or a bag or the side of a sheet or film that is designed to contact a food or drug product. The terms "food contacting surface” and’’drug- contacting surface" refer to the surface of a package such as an inner surface of a food or drug container that is in contact with, or intended for contact with, a food or drug product. When referring to a substrate that may not be in final form, the term food contacting or drug-contacting surface can refer to the surface of the substrate that is intended to be the food-contacting or drug-contacting surface in the final packaging as the term is used herein. Use of the terms“food-contacting surface” or“drug-contacting surface” should not be construed overly literally to mean that the surface itself is actually contacting the food or drug because, as will be seen herein, the surface may contain a coating or a base layer.

[0062] The term "edible," as used herein, refers to a non-toxic substance that is suitable for consumption by humans. The term“generally recognized as safe” or“GRAS”, as used herein, refers to substances generally recognized, among qualified experts, as having been adequately shown to be safe under the conditions of its intended use, for example by general recognition of safety through scientific procedures under 21 C.F.R §170.30(b) or by general recognition of safety through experience based on common use in food/drugs by a substantial history of consumption for food/drug use under 21 C.F.R §170.30(c). GRAS substances can include those substances listed in 21 C.F.R. §182. Additionally, the materials listed in the EAFUS database are those items that are directly added into food in the United States and falls under multiple 21 CFR sub-sections particularly those related to human consumption.

[0063] The phrase“safe for food or drug packaging”, as used herein, refers to substances that, based on sound scientific principals and procedures, are recognized as safe in the manner in which they are to be used where the substance will be contacting a food or drug that is intended for human consumption. Such recognition can include the likelihood of consumption of such substance and potential toxicity of the substance. Substances that are safe for food or drug packaging can include those substances that are safe under the standard described in subsection 21 U.S.C. 348(c)(3)(A). Substances that are safe for food or drug packaging can be those that are the subject of an effective premarket notifications for food/drug contact substances submitted under 21 U.S.C. 348 (h)(1). Substances that are safe for food or drug packaging can include those substances known as“indirect food additives” mentioned in Title 21 of the U.S. Code of Federal Regulations (21 CFR) Parts 175, 176, 177, and 178 as well as those substances that are exempted from regulation as food additives in accordance with 21 CFR 170.39. Substances that are safe for drug packaging are those that meet the outlined guidelines in 21 CFR 211 and meet any additional USP standard testing performed.

[0064] The term "substantially free" as used in this context means the reaction product and/or coating compositions contain less than 1000 parts per million (ppm), "essentially free" means less than 100 ppm and "completely free" means less than 20 parts per billion (ppb) of any of the above compounds or derivatives or residues thereof.

[0065] Unless otherwise indicated, the term "polymer" includes both homopolymers and copolymers (e.g., polymers of two or more different monomers) and oligomers. Similarly, unless otherwise indicated, the use of a term designating a polymer class is intended to include homopolymers, copolymers and graft copolymers.

[0066] The term“sprayable,” as used herein, means that the composition can be applied by a standard spraying device used in consumer products. In some aspects, the term sprayable means the composition can be sprayed using an air sprayer including an HPLV spray gun, an airless sprayer, or an air-assisted airless sprayer. In some aspects, a sprayable composition is one that can be sprayed at pressures of about 100 PSI, about 80 PSI, about 60 PSI, about 40 PSI, or less. In some aspects, the sprayable compositions can have a viscosity of about 150 mPas, about 100 mPas, about about 50 mPas, about 40 mPas, about 30 mPas, about 20 mPas, or less when measured with a plate/cone rotation rheometer at a shear rate of about 500 s^-1.

Waterborne coating compositions for forming surfaces and methods of making and uses thereof, especially for forming food-safe and drug-safe coatings and surfaces

[0067] As previously described in international application PCT/US17/43915 entitled “Compositions And Methods For Creating Functionalized, Roughened Surfaces And Methods Of Creating Repellant Surfaces,” substantially uniformly-textured or uniformly-textured surfaces can be formed from a one-pot spray formulation, which can be more advantageous than a hierarchically-textured surface for creating a slippery liquid-infused porous surface. Such surfaces can be created in a single application without additional multi-step treatment (e.g. boiling water treatment and surface functionalization) and with better mechanical properties than previously known. That is, a functionalized, roughened surface can be created that is substantially uniformly-textured such that the surface can immobilize a lubricating liquid (lubricant) to form a layer of liquid over and above the surface thereby presenting a smooth liquid interface with minimal, undesirable pinning points.

[0068] As described herein, substantially uniformly-textured or uniformly-textured surfaces can be formed via a one-pot spray formulation where the components and/or the surfaces formed are food-safe, e.g. are safe for food packaging. The compositions and the surfaces formed therefrom can be made from polymers, nanoparticles, and/or solvents that are edible, generally recognized as safe, safe, and/or safe for food packaging. At the same time, the choice of polymers, nanoparticles, and solvent balance a number of factors such as the composition of the nanoparticles and the binder, the compatibility of the solvent with the binder and the solvent’s ability to provide stable particle dispersions, the compatibility of the nanoparticles with the binder so that the nanoparticles may be dispersed in the final composition, the setting and/or curing time from application of the composition to its formation, and the evaporation profile of the solvent, and the surface chemistry of the base layer that is compatible with edible lubricating liquids that will spread and be retained on the surface in a robust manner.

[0069] Pinning points lead to a non-flat liquid interface conforming to the topography created by a larger length scale roughness than the nanoscale (e.g. microscale texture, potential protrusion of larger length scale peaks of underlying solids above the liquid surface, incomplete coverage of the lubricant failing to form liquid overlayer around cracks where underlying solids can be exposed acting as pinning points). Such exposed surfaces can act as a‘defect point’ where liquid can pin and contribute to increased contact angle hysteresis and as a starting point to dewet the pre-wet lubricant and eventually displace the lubricant.

[0070] Accordingly, the functionalized, roughened surface created from the compositions of the present teachings preferably is not a hierarchically-textured surface but rather a substantially uniformly-textured or a uniformly-textured surface. Such a uniformly-textured surface can be created using nanoparticles having a narrow particle size distribution such as a monodisperse population of nanoparticles. That is, a narrow particle size distribution can be described as monodispersed. By using a dispersion of suspended particles having a narrow particle size distribution, a porous or textured coating or film can be realized that has a smaller variation in its surface topography but maintains sufficient porosity to stably immobilize a lubricant within, on and over the porous coating.

[0071] In various embodiments, a narrow particle size distribution can refer to a population of nanoparticles having diameters with a standard deviation of about 90% from an average (or mean) diameter of the population of nanoparticles. In various embodiments, the narrow particle size distribution can have a standard deviation of about 80% from an average diameter, of about 75% from an average diameter, of about 70% from an average diameter, of about 60% from an average diameter, of about 50% from an average diameter, of about 40% from an average diameter, of about 30% from an average diameter, of about 20% from an average diameter, or less. In some aspects, the narrow particle size distribution refers to a population of nanoparticles having diameters within about 30 nm, within about 25 nm, within about 20 nm, within about 15 nm, within about 10 nm, within about 5 nm, or less from an average diameter of the population of nanoparticles.

[0072] The nanoparticles can have an average diameter between about 7 nm to about 1000 nm. For example, the average particle size of the nanoparticles can be about 7 nm to 200 nm, about 7 nm to about 50 nm, about 7 nm to about 25 nm, or about 7 nm to about 20 nm, about 10 nm to about 150 nm, about 10 nm to about 100 nm, about 10 nm to about 50 nm, about 40 nm to 150 nm, about 40 nm to 120 nm, about 200 nm to 500 nm, about 400 nm to 750 nm, or about 20 nm, about 50 nm, about 75 nm, about 100 nm, about 120 nm, about 150 nm, about 175 nm, about 200 nm, about 250 nm, about 300 nm, about 350 nm, about 400 nm, about 450 nm, about 500 nm, about 600 nm, about 700 nm, about 800 nm, about 900 nm, or about 1000 nm.

[0073] With respect to creation of a uniformly-textured surface rather than a hierarchically- textured surface, a hierarchically-textured surface typically refers to two different length scale features that form the porosity of the structure on the surface. The difference between the two different length scales should be at least an order of magnitude, i.e. , 10¹ or 10 times, different. Accordingly, with this hypothesis as a guide, to avoid creating a hierarchically-textured surface, the ratio of a primary feature size to a secondary feature size of solids in the composition such as nanoparticles can be less than about 10, less than about 9, less than about 8, less than about 7, less than about 6, less than about 5, less than about 4, less than about 3, or less than about 2. A primary feature size can be a particle size at the upper end of the particle size distribution range and a secondary feature size can be a particle size at the lower end of the particle size distribution. [0074] Although under an order of magnitude difference between a primary feature size and a secondary feature size can provide a textured surface of the present teachings, often hierarchical structure features are discussed in terms of micro- and nano-scaled features, which size difference is three orders of magnitude, i.e., 10³ or 1000 times, different. While such a large size difference in a particle size distribution range can create a hierarchically-textured surface, a grey area exists between this size difference and a one order of magnitude size difference. That is, a defined number as to where the cross-over occurs from one textured surface to the other is dependent on many different factors that influence the formation of the textured coating such as the composition of the nanoparticles and the binder, their compatibility with the solvent, the dispersion of the nanoparticles in the composition, the setting and/or curing time from application of the composition to its formation, and so on. Thus, a ratio of a primary size feature to a secondary size feature can be greater than 10 and can still provide a non-hierarchically-textured coating or surface, i.e., a substantially uniformly-textured coating, film or surface, using compositions and methods of the present teachings.

[0075] For example, in certain embodiments, the nanoparticles or binder can form agglomerates when applied to a substrate or surface. Agglomerates of nanoparticles or binder can be present in the compositions if they are not dispersed sufficiently or appropriately, or for other reasons such as the compatibility of the nanoparticles with the binder and/or the solvent. In such cases where agglomerates of nanoparticles or binder are present on the surface, a primary feature size can be the size of the agglomerates (e.g., an average size or a size at the upper end of the agglomerate size distribution range) and a secondary feature size can be the size of the nanoparticles or binders (e.g., an average size or a size at the lower end of the particle size distribution). In such cases, the ratio of a primary feature size to a secondary feature size can be greater than about 10, for example, greater than about 15, or greater than about 20 or greater than about 25, and provide a non-hierarchically-textured coating or surface, i.e., a substantially uniformly-textured coating or surface, using compositions and methods of the present teachings.

[0076] In these cases, without wishing to be bound to any particular theory, it is believed that because an agglomerate is composed of the nanoparticles in the composition, the surface topography of the agglomerate would be similar to the surface topography created by completely dispersed nanoparticles applied to a surface, although having the curvature of the agglomerate rather than conforming to the topography of the surface. Thus, while the largest size feature (e.g., the diameter of the agglomerate) would be larger than the largest nanoparticle size feature and could extend a greater distance from the underlying substrate or surface, a textured coating or film of the present teachings typically is not a mono-layer of nanoparticles but can contain many “layers” of nanoparticles from the surface of the substrate to the exposed surface of the coating. Consequently, a mixture of nanoparticles and agglomerates within the coating or film can present a substantially uniformly-textured surface similar to a textured surface created without any agglomerates present. Accordingly, the ratio of a primary feature size to a secondary feature size can be greater than about 10 and still provide a non-hierarchically-textured surface.

[0077] With respect to the stability of the lubricant overlayer, without wishing to be bound to any particular theory, while it is believed that the lubricant overlayer can be stabilized by the chemical affinity between it and the binder, an equal or greater amount of stability can be provided by having textured surface on top of chemical affinity. That is, a dominant factor stabilizing the lubricant overlayer can be the capillary force created by the functionalized, roughened surface texture, i.e. , porosity, of the present teachings.

[0078] For food and drug packaging applications, it is desirable to use a lubricant that is safe for food or drug packaging. In some aspects, the lubricant is an oil. In some aspects, the oil is an oil that is safe for food packaging. In some aspects, the oil is an oil that is safe for drug packaging. In some aspects, the oil is one that is generally recognized as safe. In even further aspects, the oil can be an edible oil. The chemistry of the base coat layer must therefore be chosen to be compatible with oils that meet one or more of these requirements. In addition, a higher viscosity lubricant can assist in creating a more stable lubricant overlayer with greater lubricant retention on the surface.

[0079] In one or more aspects, a surface is provided for food or dug packaging. The surface can include a low surface energy substrate having a first low-energy surface; and a base coat layer stably adhered to and coating at least a portion of the first low-energy surface. The coating compositions described herein are able to provide wetting of low-energy surfaces and can provide high quality base coat layers described herein.

[0080] In various aspects of the disclosure, the base coat layer has about 35 parts by weight to about 65 parts by weight of a low surface energy polymer, about 40 parts by weight to about 60 parts by weight of a low surface energy polymer, about 40 parts by weight to about 55 parts by weight of a low surface energy polymer, about 45 parts by weight to about 60 parts by weight of a low surface energy polymer, about 45 parts by weight to about 55 parts by weight of a low surface energy polymer, about 50 parts by weight to about 60 parts by weight of a low surface energy polymer, or about 40 parts by weight to about 50 parts by weight of a low surface energy polymer. In various aspects, the low surface energy polymer has a surface energy density of about 25 millinewtons per meter to about 45 millinewtons per meter, about 30 millinewtons per meter to about 40 millinewtons per meter, about 25 millinewtons per meter to about 40 millinewtons per meter, about 30 millinewtons per meter to about 45 millinewtons per meter, about 35 millinewtons per meter to about 40 millinewtons per meter, or about 30 millinewtons per meter to about 35 millinewtons per meter.

[0081] In various aspects, the base coat layer has about 35 parts by weight to about 55 parts by weight of nanoparticles, about 35 parts by weight to about 50 parts by weight of nanoparticles, about 37 parts by weight to about 50 parts by weight of nanoparticles, about 37 parts by weight to about 48 parts by weight of nanoparticles, about 40 parts by weight to about 48 parts by weight of nanoparticles, about 40 parts by weight to about 50 parts by weight of nanoparticles, or about 37 parts by weight to about 45 parts by weight of nanoparticles.

[0082] The base coat layer can have an outer surface opposite to the first low-energy surface, the outer surface having a substantially uniformly-textured outer surface. The outer surface is, in some aspects, uniformly textured. The outer surface can be substantially free of any cracks or surface defects. The out surface can be substantially free macro-scale texturing and/or hierarchical texturing. For example, the outer surface can have a substantially uniform nano-scale texturing.

[0083] The base coat layer can be of a very high quality, even when applied to low surface energy substrates that are difficult to coat. In various aspects of the disclosure, the base coat layer is substantially free of cracks. In some aspects, the outer surface of the base coat layer has a water contact angle of about 100° to about 140°. In some aspects, the outer surface of the base coat layer is substantially free of the nanoparticles. This can create a substantially uniformly textured substrate. The substantially uniformly-textured outer surface, in some aspects, has a nanoscale texturing. The substantially uniformly-textured outer surface is, in some aspects, free of macroscale texturing.

[0084] The base coat layer can have a variety of thicknesses. In some aspects, the base coat layer, when dried, has an average film thickness perpendicular to the first low-energy surface of about 2.5 microns to about 35 microns, about 5 microns to about 30 microns, about 2.5 microns to about 30 microns, about 5 microns to about 35 microns, about 10 microns to about 30 microns, about 5 microns to about 10 microns, about 10 microns to about 20 microns, about 20 microns to about 30 microns, or about 10 microns to about 25 microns. [0085] In various aspects, the base coat layer is not a superhydrophobic surface. In some aspects of the disclosure, the base coat layer has a mass fraction ( y ) of about 0.25 to about 0.50 or about 0.35 to about 0.45. The mass fraction is determined by the equation

where m_particles is a total mass of the hydrophobic nanoparticles in the base coat layer, and m_Poiymer '^{s a} total mass of the low surface energy polymer in the base coat layer.

[0086] The outer surface can have an oil spontaneously wetting and adhering to the outer surface of the base coat layer to form a slippery liquid overlayer. In various aspects, the oil is safe for food and drug packaging. In some aspects, the oil is a component that is generally recognized as safe. In still further aspects, the oil is an edible oil. In various aspects, the oil includes medium chain triglycerides, vegetable oil, soybean oil, canola oil, rapeseed oil, corn oil, sunflower oil, high oleic sunflower oil, coconut oil, safflower oil, peanut oil, palm oil, super olein oil, cottonseed oil, ground nut oil, olive oil, rice bran oil, safflower oil, grapeseed oil, walnut oil, flaxseed oil, macadamia nut oil, food/drug grade mineral oil, jojoba oil, algal oil, camelina oil, squalene oil, rice bran oil, juniperberry oil, patchouli oil, amyris oil, styrax oil, or a combination thereof.

[0087] The surface can be created from a variety of coating compositions. In some aspects, the coating composition includes about 6 parts by weight to about 10 parts by weight of a low surface energy polymer based upon a total weight of the coating composition; about 5 parts by weight to about 9 parts by weight of nanoparticles based upon the total weight of the coating composition; about 1 part by weight or less of a volatile base based upon the total weight of the coating composition; and about 74 parts by weight to about 87 parts by weight water based upon the total weight of the coating composition. The low surface energy polymer can be any polymer described herein.

[0088] In some aspects, the coating composition includes about 5 parts by weight to about 15 parts by weight of a low surface energy polymer, about 5 parts by weight to about 10 parts by weight of a low surface energy polymer, about 6 parts by weight to about 15 parts by weight of a low surface energy polymer, about 6 parts by weight to about 10 parts by weight of a low surface energy polymer, or about 6 parts by weight of a low surface energy polymer, about 7 parts by weight of a low surface energy polymer, about 8 parts by weight of a low surface energy polymer, about parts by weight of a low surface energy polymer, or about 10 parts by weight of a low surface energy polymer. [0089] In some aspects, the coating composition includes about 5 parts by weight to about 15 parts by weight of nanoparticles, about 5 parts by weight to about 10 parts by weight of nanoparticles, about 6 parts by weight to about 15 parts by weight of nanoparticles, about 5 parts by weight to about 9 parts by weight of nanoparticles, or about 5 parts by weight of nanoparticles, about 6 parts by weight of nanoparticles, about 7 parts by weight of nanoparticles, about 8 parts by weight of nanoparticles, or about 9 parts by weight of nanoparticles.

[0090] In some aspects, the coating composition includes about 1.5 parts, about 1.2 parts, about 1 part, about 0.8 parts, about 0.6 parts, or about 0.5 parts by weight or less of the volatile base. The coating composition is a waterborne composition and, in some instances, includes about 70 to about 95 parts water, about 74 to about 95 parts water, about 70 to about 87 parts water, about 80 to about 95 parts water, about 80 to about 90 parts water, about 80 to about 87 parts water, or at least about 80 parts or 85 parts or more of water.

[0091] In some aspects, the coating composition is sprayable. In some aspects, when the composition is sprayed onto a first low-energy surface of a low surface energy substrate and annealed, the composition forms a base layer stably adhered to the first low-energy surface. In some aspects, when the composition is sprayed onto a first low-energy surface of a low surface energy substrate, prior to drying the composition wets the first low-energy surface. In some aspects, the base layer after annealing has an outer surface opposite the first low-energy surface, the outer surface being a substantially uniformly-textured outer surface.

[0092] Methods of making the coating compositions are also provided. In some aspects, the methods include adding hydrophilic nanoparticles to water and adjusting the pH with a volatile base to form a nanoparticle dispersion; adding the nanoparticle dispersion to an aqueous dispersion of a low surface energy polymer having a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter to form the coating composition. In some aspects, the methods include adding hydrophilic nanoparticles to water and adjusting the pH with a volatile base to form a nanoparticle dispersion; heating the nanoparticle dispersion to a first elevated temperature; adding an aqueous dispersion of a low surface energy polymer to the heated nanoparticle dispersion with stirring to form the coating composition, wherein the low surface energy polymer has a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter. In some aspects, the methods include dispersing hydrophilic nanoparticles in water under high shear to form a nanoparticle dispersion; combining a mineral oil/water dispersion with an aqueous dispersion of a low surface energy polymer to form a polymer dispersion, wherein the low surface energy polymer has a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter; and combining the nanoparticle dispersion and the polymer dispersion under high shear and, if needed, adjusting the viscosity by adding additional water, to form the coating composition.

[0093] The pH of the coating composition is, in some aspects, about 9 to about 1 1.5. In some aspects, the hydrophilic nanoparticles are titanium dioxide nanoparticles having an average diameter of about 10 nm to about 50 nm and a uniform particle distribution. In some aspects, the volatile base is ammonium hydroxide.

[0094] Methods of making the base coat layers on a low-energy surface of a substrate are also provided. The methods can include spraying a coating composition provided herein onto the low- energy surface. In some aspects, the low-energy surface is treated with corona treatment or plasma treatment prior to spraying the coating composition. The methods can also include annealing the coating composition on the low-energy surface at a first elevated temperature for a first period of time to form a base coat layer. The first elevated temperature can be about 1 10°C to about 150°C, about 1 10°C to about 140°C, about 1 10°C to about 130°C, about 115°C to about 150°C, about 115°C to about 140°C, or about 1 15°C to about 130°C. The first period of time can be about 5 minutes to about 50 minutes, about 5 minutes to about 30 minutes, about 10 minutes to about 30 minutes, about 10 minutes to about 25 minutes, or about 10 minutes, about 15 minutes, about 20 minutes, or about 25 minutes.

[0095] The surfaces can be formed on a variety of low surface energy substrates. In some aspects, the substrate has a surface energy density of about 25 millinewtons per meter to about 40 millinewtons per meter, or about 25 millinewtons per meter to about 35 millinewtons per meter. In some aspects, the substrate is a high density polyethylene (HDPE) substrate, a low density polyethylene (LDPE) substrate, a polyethylene terephthalate (PET) substrate, a polypropylene (PP) substrate, a polystyrene (PS) substrate, a polyvinyl chloride (PVC) substrate, a polycarbonate (PC) substrate, or a blend or copolymer thereof. In various aspects, the substrate is selected from PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PP bottles and containers, PVC sheets and bags, and LDPE sheets and bags.

[0096] In some aspects, the volatile base can be ammonium hydroxide, dimethylaminoethanol, or a combination thereof. In some aspects, the low surface energy polymer is a polyolefin homopolymer or copolymer. In some aspects, the low surface energy polymer is polyethylene, polypropylene, or a copolymer thereof. In various aspects, the nanoparticles are titanium dioxide, colloidal nanoparticle dispersions, carbon nanoparticles, hydrophilic clay nanoparticles, or a combination thereof. The nanoparticles can by hydrophobic nanoparticles. The nanoparticles can an average diameter of about 10 nm to about 200 nm and narrow particle size distribution. In some aspects, the average diameter is about 10 nm to about 100 nm, or about 10 nm to about 50 nm. The base coat layers, forming a substantially uniformly-textured outer surface, can be coated with a variety of lubricating liquids. In some aspects, slippery surfaces can be made by applying an oil to an outer surface of the base coat layer, wherein the oil spontaneously wets and adheres to the outer surface of the base coat layer to form a slippery liquid over layer.

EXAMPLES

[0097] Now having described the embodiments of the present disclosure, in general, the following Examples describe some additional embodiments of the present disclosure. While embodiments of the present disclosure are described in connection with the following examples and the corresponding text and figures, there is no intent to limit embodiments of the present disclosure to this description. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of embodiments of the present disclosure.

Example 1 : Co-Solvent Approaches for Making Surfaces on Polypropylene

[0098] Polypropylene was chosen as the low-energy surface for testing purposes due to the challenges associated with forming quality films on polypropylene using waterborne compositions. Co-solvent approaches were tested for their ability to form quality surfaces with uniform nanostructure and dynamic contact angles of at least 120° without pinning. Co-solvents tested included methanol, ethanol, and isopropyl alcohol.

[0099] The general procedure for creating the compositions included:

[0100] (1) Hydrophobic silica nanoparticles were added to a mixture of water and co-solvent and wetting agent. A variety of wetting agents were tested to achieve good wetting, such as Tivida FL2500 (anionic wetting agent), Tego Wet KL 245 (polyether siloxane copolymer), Tego Wet 270 (polyether siloxane copolymer), Tego TWIN 4100 (siloxane based gemini surfactant), and Tego Wet 251 (polyether siloxane copolymer).

[0101] (2) An aqueous polyolefin dispersion was prepared containing 42% polyolefin by weight.

[0102] (3) The hydrophobic silica nanoparticle dispersion was combined with the polyolefin dispersion with mechanical stirring to produce the coating composition. [0103] Various coating compositions were prepared with the proportions listed in the following table.

[0104] Without the presence of the wetting agent the films formed cracks. Even after the addition of a wetting agent (anionic wetting agent) the cracks remained. As depicted in FIGS. 4A-4H, the adjustment of the particle:binder ratio did not help to remedy the cracks in films formed from compositions with added wetting agent.

[0105] Based on the co-solvents tested, co-solvents of methanol and very small concentrations of ethanol helped to form homogenous dispersions. The drying profile of water is very slow and, relatively speaking, the drying profile of methanol is very fast. In order to better control the drying profiles, a combination of ethanol and I PA were tested to better control the drying profile (FIG. 5). As depicted in FIG. 6, even when homogenous dispersion was achieved, the final film quality was poor where there was further phase separation.

[0106] In order to make a homogeneous dispersion between these components we found that a large amount of co-solvent and wetting agent was required. Without the addition of the co-solvent and/or the wetting agent the particles would float on top of the surface. Even when a homogenous dispersion was achieved the final film quality was poor where there was further phase separation. The compositions and films presented in this example were not fully waterborne due to the use of organic co-solvents, and still the films were not very cohesive and exhibited many cracks. In addition, not all ingredients are approved for use in food or drug packaging.

Example 2: Use of Surfactant and Wax to Compatiblize Water-Based Compositions

[0107] Based on the results from Example 1 , surfactants (DBE 712) carnauba wax powder and acetone were tested to see if they could stabilize the system and improve the film formation respectively. The general procedure for creating the compositions included:

[0108] (1) Carnauba wax powder and hydrophobic silica particles were ultrasonicated in acetone. [0109] (2) The dispersion from the previous step was added to the 42 wt% polyolefin dispersion along with the surfactant and water.

[0110] (3) The composition was ultrasonicated to yield a homogenous dispersion.

[0111] Various coating compositions were prepared with the proportions listed in the following table.

[0112] The melting point of the carnauba wax was experimentally determined to find the minimum processing temperatures required for the carnauba wax (FIG. 7). The films were prepared and examined via SEM. Although the film quality could be improved by adjusting the particle:wax ratio, the films were still cracking and were powdery (FIG. 8). In order to improve the film cohesion, the particle loading was decreased (FIG. 9), but as the particle loading was decreased enough to get surfaces that were not powdery the nanostructure was also not maintained. In another attempt to reduce the powdery nature of the surface, the concentration of the polyolefin dispersion was increased with a fixed amount of particles, however the nanotexture was not present at the surface upon increasing the polyolefin dispersion (FIG. 10). Compared to the FIG. 9 the total binder content (carnauba wax+polyolefin dispersion) is higher in FIG. 10. Decreasing the carnauba wax concentration was found to help with forming a better film (FIG. 11) but the nanotexture was still not uniform. Overall, the films produced were powdery and there was phase separation between the wax and the polyolefin dispersion with many cracks.

Example 3: Replacing Hydrophobic Silica Particles With Titanium Dioxide

[0113] In an effort to increase compatibility between the components, the hydrophobic silica nanoparticles from Example 2 were replaced with titanium dioxide particles. Compositions were prepared according to the procedure from Example 2 (replacing the silica with titanium dioxide). Various coating compositions were prepared with the proportions listed in the following table.

[0114] Large amounts of acetone were still required to compatibilize the carnauba wax into the system. Even with large amounts of acetone, the films were of low quality and showed many defects and cracks in SEM.

Example 4: Fully waterborne compositions with mineral oil plasticizer

[0115] In an effort to remove co-solvent (for a fully waterborne composition), the carnauba wax was removed. The general method for preparing these formulations was as follows (see FIG. 12):

[0116] (1) Titanium dioxide particles were dispersed in Dl water via ul.

[0117] (2) Mineral oil and water (pH~9) were ultrasonicated and added to a 42 wt% polyolefin dispersion with ultrasonication (pH~11).

[0118] (3) The titanium dioxide dispersion (pH~4) was added to the above mixture.

[0119] (4) The final formulation was ultrasonicated and diluted (as necessary) with additional water to achieve a sprayable consistency at a pH of about 9.97.

[0120] Various coating compositions were prepared with the proportions listed in the following table.

[0121] The amount of mineral oil was used to improve the film forming properties of the polyolefin dispersion and improve the mobility of the titanium dioxide during the annealing process. As can be seen in FIG. 13, the addition of mineral oil acts as a plasticizer that improves film mobility during annealing and improves film quality. The amount of mineral oil was fine tuned to where there is a noticeable effect on the matrix. Furthermore, the specific type and viscosity of the hydrocarbon oil impacts the crystallinity and film formation. As depicted in FIG. 14, depending on the type of hydrocarbon oil used and the viscosity the crystallinity of the polyolefin binder can be tuned. This is important because without the incorporation of the mineral oil into the system the final films are brittle and present more defects on the surface that results in water pinning to the surface.

[0122] Having found compositions with suitable film-forming properties of polyolefin in a waterborne system, the impact of the particle loading was determined on the water pinning and surface properties. As depicted in FIG. 15, the optimal particle loading was experimentally determined where the criteria was looking at the formation of nano-texture on the surface, the contact angle on the surface and the pinning of water droplets on the surface. It was important to maintain performance while ensuring that there was no pinning of water droplets on the surface.

[0123] The amount of additional water was reduced and demonstrated to improve application quality by optimizing the sagging, while still maintaining the nanotexture on the surface. Sagging is a defect in coatings caused by gravity- driven flow on vertical surfaces. Sags can be subtle or obvious and can lead to surface imperfections such as reduced leveling, mottling, cracking and pinhole formation. Results are depicted in FIGS. 16A-16C.

[0124] The coating compositions are shelf stable. As demonstrated in FIG. 17, the surfaces prepared within 24 hours of mixing the composition demonstrated similar surface properties with well-maintained nanostructures.

[0125] Foaming has an impact on the film properties, especially for the thicker coatings. Increasing mixing time was found to create smaller foams which reduced the impact on the final foam. FIG. 18 and FIG. 19. The use of chemical defoamers resulted in reduction of performance such that there was wetting of water on the surface (migration of small species to the surface), so instead physical defoaming was investigated as an option where the void spaces from foam were collapsed to obtain a more uniform nanotexture. Physical defoaming of the coating compositions produced films with reduced defects (FIG. 20) and improved the uniformity and general quality of the nanotextures formed (FIG. 21). To examine the effects of defoaming, the lubricant was applied to the samples using a spin coater for 1 min at 1000 rpm and then different shears were applied and the droplet speed of water was measured by applying a 15 mI_ droplet of water on the surface at a tilt angle of 15 degree. The physical defoaming was also found to improve the lubricant retention and performance of the coated surfaces (FIGS. 22A-22C).

[0126] In order to improve slip at the surfaces and eliminate dynamic wetting, paraffin wax was added to the coating compositions. Various surfaces were prepared with the following compositions

[0127] The effects of the addition of wax on the nanotexture and wetting properties was examined. The addition of the wax was found to decrease the dynamic wetting behavior (FIG. 23), however if too much wax was added then the top lubricant layer would not fully wet the surface. The amount of wax was fine-tuned (FIG. 24) to maintain the nanotexture on the surface and prevent dynamic wetting while still providing a surface that is wet by the lubricant.

[0128] The approaches in this example were able to meet the material requirements, however the process for forming the surface is time intensive and is not readily scalable in industrial settings.

Example 5. Fully waterborne coating compositions with ammonium hydroxide

In an effort to have a fully waterborne composition and a process that was more scalable, several processes were examined using titanium dioxide particles with ammonium hydroxide.

[0129] Method #1

• 12 wt% titanium dioxide particles are incrementally added to water with adjusted pH ~11 using ammonium hydroxide

• titanium dioxide dispersion is added to the 42% polyolefin dispersion let down dispersion in water • the final formulation is applied to substrates and annealed at 125°C for 15 min [0130] Method #2

• The dispersion is heated to 90°C under mechanical stir

• Once at equilibrium the 42 wt% polyolefin dispersion is added dropwise to the heated dispersion

• The solution is allowed to stir for 5-6 h and the viscosity is adjusted by the addition of water (pH adjusted to—11) to maintain stir conditions

• The final formulation is applied to the substrates and annealed at 125°C for 15 min

• Alternatively, the formulation can be sprayed hot or to a heated substrate and allowed to dry at room temperature

[0131] Method #3

• Titanium dioxide is dispersed in water under high shear

• 42 wt% polyolefin dispersion is combined with a mineral oil in water emulsion under high shear

• the particle dispersion is added to the polymer/oil dispersion under high shear

• water is added to adjust the final viscosity to a sprayable formulation

• the final formulation is applied to the substrate and annealed at 125°C for 15 min

[0132] Top Coat application:

[0133] Method #1 : The top oil layer can be applied via spray at room temperature

[0134] Method #2: The oil can be applied as a hot spray on to the base coat

[0135] Various coating compositions were prepared using the methods described above and with the proportions listed in the table below.

[0136] The amount of ammonium hydroxide (to adjust pH) and the titanium dioxide particle loading was optimized to achieve optimal and robust nanotexturing on the surface (FIG. 25 and FIG. 26). It was observed that there is an optimal point between particle loading and ammonium hydroxide concentration to result in high quality nanotexture (FIGS. 27A-27B).

[0137] Optimizing the water content was used to improve the formulations for scalable spray application. The sagging and leveling of the compositions were optimized for various polyolefin dispersion/Ti0₂ ratios by adjusting the amount of water (FIG. 28).

[0138] The dynamic wetting was minimized by controlling the amount of titanium dioxide which partitioned to the surface. With a higher water concentration the system stays mobile for longer during the annealing process, whereas in a lower water concentration system the system doesn’t have as much time to rearrange (FIG. 29). It was also observed that, as the coating thickness increased there was an increased appearance of cracking in the surface (FIG. 30). Also, annealing first (as opposed to after drying) was found to significantly impact the cracking of the surface (FIG. 31). If the water concentration was too low, cracking was observed, however with too high water level sagging was evident in the coatings (FIG. 32). The presence of macro-scale texture in the surface was also found to be dependent upon the processing temperature (FIG. 33).

[0139] The methods of this example presented a scalable process and has been produced on the gallon size. The drying/annealing and the amounts of components were found to impact the final film quality to achieve quality films without cracking, sagging, or levelling and without pinning, but while maintaining the uniform nanostructure and the wetting of the surface by lubricant.

[0140] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations, and are set forth only for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above- described embodiments of the disclosure without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure.

[0141] The various aspects of the invention will be better understood by reading the following aspects, which should not be confused with the claims.

[0142] Aspect 1. A surface for food or drug packaging comprising: (a) a low surface energy substrate having a first low-energy surface; (b) a base coat layer stably adhered to and coating at least a portion of the first low-energy surface, the base coat layer comprising: (i) about 40 parts by weight to about 60 parts by weight of a low surface energy polymer having a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter; (ii) about 37 parts by weight to about 50 parts by weight of nanoparticles; and (iii) an outer surface opposite to the first low-energy surface, the outer surface comprising a substantially uniformly-textured outer surface.

[0143] Aspect 2. The surface according to any one of Aspects 1-20, further comprising an oil spontaneously wetting and adhering to the outer surface of the base coat layer to form a slippery liquid overlayer wherein the oil is safe for food or drug packaging, generally recognized as safe, and/or is edible.

[0144] Aspect 3. The surface according to any one of Aspects 1-20, wherein the outer surface of the base coat layer is substantially free of cracks.

[0145] Aspect 4. The surface according to any one of Aspects 1-20, wherein the outer surface of the base coat layer has a water contact angle of about 100° to about 140°.

[0146] Aspect 5. The surface according to any one of claims 1-4, wherein the outer surface of the base coat layer is substantially free of the nanoparticles.

[0147] Aspect 6. The surface according to any one of Aspects 1-20, wherein the substantially uniformly-textured outer surface comprises nanoscale texturing.

[0148] Aspect 7. The surface according to any one of Aspects 1-20, wherein the substantially uniformly-textured outer surface is free of macroscale texturing.

[0149] Aspect 8. The surface according to any one of Aspects 1-20, wherein the base coat layer, when dried, has an average film thickness perpendicular to the first low-energy surface of about 5 microns to about 30 microns.

[0150] Aspect 9. The surface according to any one of Aspects 1-20, wherein the base coat layer has a mass fraction ( y ) of about 0.25 to about 0.50; wherein the mass fraction is determined by the equation y = - ^mpartwies - where m_particles is a total mass of the hydrophobic

nanoparticles in the base coat layer, and m_poiymer is a total mass of the low surface energy polymer in the base coat layer.

[0151] Aspect 10. The surface according to any one of Aspects 1-20, wherein the mass fraction is about 0.35 to about 0.45. [0152] Aspect 11. The surface according to any one of Aspects 1-20, wherein the low surface energy polymer is a polyolefin homopolymer or copolymer.

[0153] Aspect 12. The surface according to any one of claims 1-11 , wherein the low surface energy polymer is selected from the group consisting of polyethylene, polypropylene, and copolymers thereof.

[0154] Aspect 13. The surface according to any one of Aspects 1-20, wherein the nanoparticles are selected from the group consisting of titanium dioxide, colloidal nanoparticle dispersions, carbon nanoparticles, hydrophilic clay nanoparticles, and a combination thereof.

[0155] Aspect 14. The surface according to any one of Aspects 1-20, wherein the nanoparticle are hydrophobic nanoparticles.

[0156] Aspect 15. The surface according to any one of Aspects 1-20, wherein the nanoparticles have an average diameter of about 10 nm to about 200 nm and narrow particle size distribution.

[0157] Aspect 16. The surface according to any one of Aspects 1-20, wherein the average diameter is about 10 nm to about 100 nm, or about 10 nm to about 50 nm.

[0158] Aspect 17. The surface according to any one of Aspects 1-20, wherein the low surface energy substrate has a surface energy density of about 25 millinewtons per meter to about 40 millinewtons per meter, or about 25 millinewtons per meter to about 35 millinewtons per meter.

[0159] Aspect 18. The surface according to any one of Aspects 1-20, wherein the low surface energy substrate comprises a high density polyethylene (HDPE) substrate, a low density polyethylene (LDPE) substrate, a polyethylene terephthalate (PET) substrate, a polypropylene (PP) substrate, a polystyrene (PS) substrate, a polyvinyl chloride (PVC) substrate, a polycarbonate (PC) substrate, and blends and copolymers thereof.

[0160] Aspect 19. The surface according to any one of Aspects 1-20, wherein the substrate is selected from the group consisting of PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PP bottles and containers, PVC sheets and bags, and LDPE sheets and bags.

[0161] Aspect 20. The surface according to any one of Aspects 1-20, wherein the oil is selected from the group consisting of medium chain triglycerides, vegetable oil, soybean oil, canola oil, rapeseed oil, corn oil, sunflower oil, high oleic sunflower oil, coconut oil, safflower oil, peanut oil, palm oil, super olein oil, cottonseed oil, ground nut oil, olive oil, rice bran oil, safflower oil, grapeseed oil, walnut oil, flaxseed oil, macadamia nut oil, food/drug grade mineral oil, jojoba oil, algal oil, camelina oil, squalene oil, rice bran oil, juniperberry oil, patchouli oil, amyris oil, styrax oil and a combination thereof.

[0162] Aspect 21. A coating composition for forming a base coat layer on a low surface energy substrate, the coating composition comprising: (i) about 6 parts by weight to about 10 parts by weight of a low surface energy polymer based upon a total weight of the coating composition, wherein the low surface energy polymer has a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter; (ii) about 5 parts by weight to about 9 parts by weight of nanoparticles based upon the total weight of the coating composition; (iii) about 1 part by weight or less of a volatile base based upon the total weight of the coating composition; and (iv) about 74 parts by weight to about 87 parts by weight water based upon the total weight of the coating composition.

[0163] Aspect 22. The coating composition according to any one of Aspects 21-30, wherein the low surface energy polymer is a polyolefin homopolymer or copolymer.

[0164] Aspect 23. The coating composition according to any one of Aspects 21-30, wherein the low surface energy polymer is selected from the group consisting of polyethylene, polypropylene, and copolymers thereof.

[0165] Aspect 24. The coating composition according any one of Aspects 21-30, wherein the nanoparticles are selected from the group consisting of titanium dioxide, colloidal nanoparticle dispersions, carbon nanoparticles, hydrophilic clay nanoparticles, and a combination thereof.

[0166] Aspect 25. The coating composition according to any one of Aspects 21-30, wherein the nanoparticles are hydrophobic nanoparticles.

[0167] Aspect 26. The coating composition according to any one of Aspects 21-30, wherein the nanoparticles have an average diameter of about 10 nm to about 200 nm and narrow particle size distribution.

[0168] Aspect 27. The coating composition according to any one of Aspects 21-30, wherein the average diameter is about 10 nm to about 100 nm, or about 10 nm to about 50 nm.

[0169] Aspect 28. The coating composition according to any one of Aspects 21-30, wherein the volatile base is selected from the group consisting of ammonium hydroxide, dimethylaminoethanol, and a combination thereof. [0170] Aspect 29. The coating composition according to any one of Aspects 21-30, wherein the composition is sprayable .

[0171] Aspect 30. The coating composition according to any one of Aspects 21-30, wherein when the composition is sprayed onto a first low-energy surface of a low surface energy substrate and annealed, the composition forms a base layer stably adhered to the first low-energy surface; and wherein the base layer has an outer surface opposite the first low-energy surface, the outer surface comprising a substantially uniformly-textured outer surface.

[0172] Aspect 31. A method of making a coating composition according to any one of Aspects 21-30, the method comprising: adding hydrophilic nanoparticles to water and adjusting the pH with a volatile base to form a nanoparticle dispersion; adding the nanoparticle dispersion to an aqueous dispersion of a low surface energy polymer having a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter to form the coating composition.

[0173] Aspect 32. A method of making a coating composition according to any one of Aspects 21-30, the method comprising: adding hydrophilic nanoparticles to water and adjusting the pH with a volatile base to form a nanoparticle dispersion; heating the nanoparticle dispersion to a first elevated temperature; adding an aqueous dispersion of a low surface energy polymer to the heated nanoparticle dispersion with stirring to form the coating composition, wherein the low surface energy polymer has a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter.

[0174] Aspect 33. A method of making a coating composition according to any one of Aspects 21-30, the method comprising: dispersing hydrophilic nanoparticles in water under high shear to form a nanoparticle dispersion; combining a mineral oil/water dispersion with an aqueous dispersion of a low surface energy polymer to form a polymer dispersion, wherein the low surface energy polymer has a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter; and combining the nanoparticle dispersion and the polymer dispersion under high shear and, if needed, adjusting the viscosity by adding additional water, to form the coating composition.

[0175] Aspect 34. The method according to any one of Aspects 31-35, wherein the pH of the coating composition is about 9 to about 1 1.5.

[0176] Aspect 35. The method according to any one of Aspects 31-35, wherein the hydrophilic nanoparticles are titanium dioxide nanoparticles having an average diameter of about 10 nm to about 50 nm and a uniform particle distribution; wherein the low surface energy polymer is a copolymer of polyethylene and polypropylene; and wherein the volatile base is ammonium hydroxide.

[0177] Aspect 36. A method of making a surface on a low surface energy substrate, the method comprising spraying a composition according to any one of Aspects 21-30 onto a first low-energy surface of the low surface energy substrate.

[0178] Aspect 37. The method according to any one of Aspects 36-42, further comprising annealing the composition at a first elevated temperature for a first period of time to form the base coat layer.

[0179] Aspect 38. The method according to any one of Aspects 36-42, wherein the low surface energy substrate has a surface energy density of about 25 millinewtons per meter to about 40 millinewtons per meter, or about 25 millinewtons per meter to about 35 millinewtons per meter.

[0180] Aspect 39. The method according to any one of Aspects 36-42, wherein the low surface energy substrate comprises a high density polyethylene (HDPE) substrate, a low density polyethylene (LDPE) substrate, a polyethylene terephthalate (PET) substrate, a polypropylene (PP) substrate, a polystyrene (PS) substrate, a polyvinyl chloride (PVC) substrate, a polycarbonate (PC) substrate, and blends and copolymers thereof.

[0181] Aspect 40. The method according to any one of Aspects 36-42, wherein the substrate is selected from the group consisting of PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PP bottles and containers, PVC sheets and bags, and LDPE sheets and bags.

[0182] Aspect 41. The method according to any one of Aspects 36-42, further comprising applying an oil to an outer surface of the base coat layer, wherein the oil spontaneously wets and adheres to the outer surface of the base coat layer to form a slippery liquid over layer.

[0183] Aspect 42. The method according to any one of Aspects 36-42, wherein the oil is selected from the group consisting of medium chain triglycerides, vegetable oil, soybean oil, canola oil, rapeseed oil, corn oil, sunflower oil, high oleic sunflower oil, coconut oil, safflower oil, peanut oil, palm oil, super olein oil, cottonseed oil, ground nut oil, olive oil, rice bran oil, safflower oil, grapeseed oil, walnut oil, flaxseed oil, macadamia nut oil, food/drug grade mineral oil, jojoba oil, algal oil, camelina oil, squalene oil, rice bran oil, juniperberry oil, patchouli oil, amyris oil, styrax oil and a combination thereof.

[0184]

Claims

We claim:

1. A surface for food or drug packaging comprising:

(a) a low surface energy substrate having a first low-energy surface;

(b) a base coat layer stably adhered to and coating at least a portion of the first low- energy surface, the base coat layer comprising:

(i) about 40 parts by weight to about 60 parts by weight of a low surface energy polymer having a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter;

(ii) about 37 parts by weight to about 50 parts by weight of nanoparticles; and

(iii) an outer surface opposite to the first low-energy surface, the outer surface comprising a substantially uniformly-textured outer surface.

2. The surface according to claim 1 , further comprising an oil spontaneously wetting and adhering to the outer surface of the base coat layer to form a slippery liquid overlayer;

wherein the oil is safe for food or drug packaging, generally recognized as safe, and/or is edible.

3. The surface according to claim 1 , wherein the outer surface of the base coat layer is substantially free of cracks.

4. The surface according to claim 1 , wherein the outer surface of the base coat layer has a water contact angle of about 100° to about 140°.

5. The surface according to claim 4, wherein the outer surface of the base coat layer is substantially free of the nanoparticles.

6. The surface according to claim 5, wherein the substantially uniformly-textured outer surface comprises nanoscale texturing.

7. The surface according to claim 6, wherein the substantially uniformly-textured outer surface is free of macroscale texturing.

8. The surface according to claim 1 , wherein the base coat layer, when dried, has an average film thickness perpendicular to the first low-energy surface of about 5 microns to about 30 microns.

9. The surface according to claim 7, wherein the base coat layer has a mass fraction {y) of about 0.25 to about 0.50;

wherein the mass fraction is determined by the equation

where m_particies is a total mass of the hydrophobic nanoparticles in the base coat layer, and m_poiymer is a total mass of the low surface energy polymer in the base coat layer.

10. The surface according to claim 9, wherein the mass fraction is about 0.35 to about 0.45.

11. The surface according to any one of claims 1-10, wherein the low surface energy polymer is a polyolefin homopolymer or copolymer.

12. The surface according to any one of claims 1-10, wherein the low surface energy polymer is selected from the group consisting of polyethylene, polypropylene, and copolymers thereof.

13. The surface according to claim 11 , wherein the nanoparticles are selected from the group consisting of titanium dioxide, colloidal nanoparticle dispersions, carbon nanoparticles, hydrophilic clay nanoparticles, and a combination thereof.

14. The surface according to claim 13, wherein the nanoparticle are hydrophobic nanoparticles.

15. The surface according to clam 13, wherein the nanoparticles have an average diameter of about 10 nm to about 200 nm and narrow particle size distribution.

16. The surface according to claim 15, wherein the average diameter is about 10 nm to about 50 nm.

17. The surface according to any one of claims 1-10, wherein the low surface energy substrate has a surface energy density of about 25 millinewtons per meter to about 40 millinewtons per meter.

18. The surface according to any one of claims 1-10, wherein the low surface energy substrate comprises a high density polyethylene (HDPE) substrate, a low density polyethylene (LDPE) substrate, a polyethylene terephthalate (PET) substrate, a polypropylene (PP) substrate, a polystyrene (PS) substrate, a polyvinyl chloride (PVC) substrate, a polycarbonate (PC) substrate, and blends and copolymers thereof.

19. The surface according to any one of claims 1-10, wherein the substrate is selected from the group consisting of PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PP bottles and containers, PVC sheets and bags, and LDPE sheets and bags.

20. The surface according to any one of claims 1-10, wherein the oil is selected from the group consisting of medium chain triglycerides, vegetable oil, soybean oil, canola oil, rapeseed oil, corn oil, sunflower oil, high oleic sunflower oil, coconut oil, safflower oil, peanut oil, palm oil, super olein oil, cottonseed oil, ground nut oil, olive oil, rice bran oil, safflower oil, grapeseed oil, walnut oil, flaxseed oil, macadamia nut oil, food/drug grade mineral oil, jojoba oil, algal oil, camelina oil, squalene oil, rice bran oil, juniperberry oil, patchouli oil, amyris oil, styrax oil and a combination thereof.

21. A coating composition for forming a base coat layer on a low surface energy substrate, the coating composition comprising:

(i) about 6 parts by weight to about 10 parts by weight of a low surface energy polymer based upon a total weight of the coating composition, wherein the low surface energy polymer has a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter;

(ii) about 5 parts by weight to about 9 parts by weight of nanoparticles based upon the total weight of the coating composition;

(iii) about 1 part by weight or less of a volatile base based upon the total weight of the coating composition; and

(iv) about 74 parts by weight to about 87 parts by weight water based upon the total weight of the coating composition.

22. The coating composition according to claim 21 , wherein the low surface energy polymer is a polyolefin homopolymer or copolymer.

23. The coating composition according to claim 21 , wherein the low surface energy polymer is selected from the group consisting of polyethylene, polypropylene, and copolymers thereof.

24. The coating composition according to claim 23, wherein the nanoparticles are selected from the group consisting of titanium dioxide, colloidal nanoparticle dispersions, carbon nanoparticles, hydrophilic clay nanoparticles, and a combination thereof.

25. The coating composition according to claim 23, wherein the nanoparticles are hydrophobic nanoparticles.

26. The coating composition according to claim 24, wherein the nanoparticles have an average diameter of about 10 nm to about 200 nm and narrow particle size distribution.

27. The coating composition according to claim 26, wherein the average diameter is about 10 nm to about 100 nm.

28. The coating composition according to any one of claims 21-27, wherein the volatile base is selected from the group consisting of ammonium hydroxide, dimethylaminoethanol, and a combination thereof.

29. The coating composition according to any one of claims 21-27, wherein the composition is sprayable .

30. The coating composition according to any one of claims 21-27, wherein when the composition is sprayed onto a first low-energy surface of a low surface energy substrate and annealed, the composition forms a base layer stably adhered to the first low-energy surface; and

wherein the base layer has an outer surface opposite the first low-energy surface, the outer surface comprising a substantially uniformly-textured outer surface.

31. A method of making a coating composition according to any one of claims 21-30, the method comprising: adding hydrophilic nanoparticles to water and adjusting the pH with a volatile base to form a nanoparticle dispersion;

adding the nanoparticle dispersion to an aqueous dispersion of a low surface energy polymer having a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter to form the coating composition.

32. A method of making a coating composition according to any one of claims 21-30, the method comprising:

adding hydrophilic nanoparticles to water and adjusting the pH with a volatile base to form a nanoparticle dispersion;

heating the nanoparticle dispersion to a first elevated temperature;

adding an aqueous dispersion of a low surface energy polymer to the heated

nanoparticle dispersion with stirring to form the coating composition,

wherein the low surface energy polymer has a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter.

33. A method of making a coating composition according to any one of claims 21-30, the method comprising:

dispersing hydrophilic nanoparticles in water under high shear to form a nanoparticle dispersion;

combining a mineral oil/water dispersion with an aqueous dispersion of a low surface energy polymer to form a polymer dispersion, wherein the low surface energy polymer has a surface energy density of about 30 millinewtons per meter to about 40 millinewtons per meter; combining the nanoparticle dispersion and the polymer dispersion under high shear and, if needed, adjusting the viscosity by adding additional water, to form the coating composition.

34. The method according to any one of claims 31-33, wherein the pH of the coating composition is about 9 to about 11.5.

35. The method according to any one of claims 31-33, wherein the hydrophilic nanoparticles are titanium dioxide nanoparticles having an average diameter of about 10 nm to about 50 nm and a uniform particle distribution;

wherein the low surface energy polymer is a copolymer of polyethylene and

polypropylene; and

wherein the volatile base is ammonium hydroxide.

36. A method of making a surface on a low surface energy substrate, the method comprising spraying a composition according to any one of claims 21-30 onto a first low-energy surface of the low surface energy substrate.

37. The method according to claim 36, further comprising annealing the composition at a first elevated temperature for a first period of time to form the base coat layer.

38. The method according to claim 36 or claim 37, wherein the low surface energy substrate has a surface energy density of about 25 millinewtons per meter to about 40 millinewtons per meter.

39. The method according to claim 36, wherein the low surface energy substrate comprises a high density polyethylene (HDPE) substrate, a low density polyethylene (LDPE) substrate, a polyethylene terephthalate (PET) substrate, a polypropylene (PP) substrate, a polystyrene (PS) substrate, a polyvinyl chloride (PVC) substrate, a polycarbonate (PC) substrate, and blends and copolymers thereof.

40. The method according to claim 36, wherein the substrate is selected from the group consisting of PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PP bottles and containers, PVC sheets and bags, and LDPE sheets and bags.

41. The method according to claim 36, further comprising applying an oil to an outer surface of the base coat layer, wherein the oil spontaneously wets and adheres to the outer surface of the base coat layer to form a slippery liquid over layer.

42. The method according to claim 41 , wherein the oil is selected from the group consisting of medium chain triglycerides, vegetable oil, soybean oil, canola oil, rapeseed oil, corn oil, sunflower oil, high oleic sunflower oil, coconut oil, safflower oil, peanut oil, palm oil, super olein oil, cottonseed oil, ground nut oil, olive oil, rice bran oil, safflower oil, grapeseed oil, walnut oil, flaxseed oil, macadamia nut oil, food/drug grade mineral oil, jojoba oil, algal oil, camelina oil, squalene oil, rice bran oil, juniperberry oil, patchouli oil, amyris oil, styrax oil and a combination thereof.