CN103013374A - Bionic anti-sticking lyophobic and oleophobic pasting film - Google Patents

Abstract

The bionic anti-adhesive hydrophobic and oleophobic film belongs to the technical field of polytetrafluoroethylene products. The surface of the film layer of the present invention has a first-level convex-hull structure and a second-level convex-hull structure. The convex-hull structure is composed of convex-hull structural units. The bottom of the convex hull structural unit is circular, regular triangle, regular quadrilateral or regular hexagonal; the convex hull is bowl-shaped, cylindrical, conical, triangular prism, quadrangular prism or hexagonal prism; the present invention can be bent and folded arbitrarily, Used on irregular surfaces, the original hydrophilic and lipophilic surfaces can be transformed into superhydrophobic and oleophobic surfaces, which can be widely used in automobiles, kitchen utensils, electronic products and other fields.

Description

Bionic anti-adhesive hydrophobic and oleophobic film

technical field

The invention belongs to the technical field of polytetrafluoroethylene products, and in particular relates to a bionic anti-adhesive hydrophobic and oleophobic film.

Background technique

In daily life, due to the short lifespan of car wiper rubber strips, it needs to be replaced frequently; the front and rear fenders and the lower part of the door are easily dirty due to the mud thrown by the wheels in rainy and snowy weather; electronic products are accidentally dropped into the water; kitchen utensils are full of oil and are difficult to clean, etc. A series of questions plagued us. The reason is that the contact angle between water droplets and oil droplets and the surface of the device is small, and the device cannot be well hydrophobic and oleophobic.

The molecular structure of polytetrafluoroethylene is (-CF2-CF2-)n, which is a highly symmetrical non-polar linear polymer material with extremely low surface free energy and highly hydrophobic surface. At present, polytetrafluoroethylene film The preparation process of PTFE is relatively mature, but the contact angle between smooth surface polytetrafluoroethylene film and water is difficult to reach 150°, so as to realize the superhydrophobicity of the film. In the field of research on bionic non-smooth surfaces, Patent No. 01226143.2 points out that according to the principles of bionics, structural units with certain geometric shapes are regularly distributed on the surface of components. However, its characteristic size is large, and it is a first-level non-smooth structure. In practical engineering applications, it can only reduce the viscosity, but the anti-sticking effect is not obvious. When the size is reduced to nanometers, although it can achieve a very perfect anti-sticking effect, and nanomaterials bring many benefits to humans, they also bring many safety hazards. Nanomaterials are not easy to degrade and have strong penetrability. Nanomaterials pose certain threats to the environment and human health. To solve these problems, the present invention uses low surface energy materials to construct an environment-friendly film with a certain characteristic size, imitating the special surface secondary composite structure of lotus leaves.

Contents of the invention

The purpose of the present invention is to build a secondary rough surface structure on the basis of the low surface free energy of the material itself, paste it on the surface of the workpiece that needs waterproof and oil resistance, apply the anti-adhesive hydrophobic and oleophobic properties of the film, and keep the surface that is easy to stain Clean, dry glass surface, improve the service life of electronic products.

The present invention consists of a film layer 1 and an adhesive coating 2, wherein the surface of the film layer 1 has a first-level convex-hull structure and a second-level convex-hull structure, the convex-hull structure is composed of convex-hull structural units, and the convex-hull structural unit The bottom is circular, regular triangle, regular quadrilateral or regular hexagonal; the convex hull is bowl-shaped, cylindrical, conical, triangular prism, quadrangular prism or hexagonal prism; the thickness _d1 of the film layer is 0.1-0.3mm, Adhesive coating thickness _d2 is 0.01-0.03mm.

For the first-level convex-hull structure and the second-level convex-hull structure, the structural area occupancy rate represents the ratio of the sum of the areas of the circumscribed circles at the bottom of the convex-hull structures at all levels to the surface area of the substrate, which is determined by the following formula:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; l</span>}}{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&pi;</span>}{\mathrm{<span\; class="notranslate">\; R</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; l</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; l</span>}}{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&pi;</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; l</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right.$

Among them: P ₁ indicates the area occupancy rate of the first-level convex-hull structure; P ₂ indicates the area occupancy rate of the second-level convex-hull structure; l indicates the side length of the regular quadrilateral processing area; Distance; d represents the distance between the second-level convex hull structure units; R represents the radius of the circumscribed circle at the bottom of the first-level convex hull; r represents the radius of the circumscribed circle at the bottom of the second-level convex hull.

The convex hull height H of the first-stage convex-hull structure and the radius R of the circumscribed circle at the bottom of the convex hull are 10-100um, the convex-hull height H is 5-100um, and H≤R; the convex-hull structure of the second stage The radius r of the circumscribed circle at the bottom of the package is 1-10um, the height h of the convex hull is 0.5-10um, and h≤r.

The area occupancy rate of the first-level convex-hull structure P ₁ ≥ 30%, and the area occupancy rate of the second-level convex-hull structure P ₂ ≥ 30%.

The surface of the film layer with the first-level convex-hull structure and the second-level convex-hull structure is made of polytetrafluoroethylene resin added with 6% fluorine-containing surfactant (FS) and hot-pressed through a mold.

The mold has a non-smooth surface corresponding to the first-level convex-hull structure and the second-level convex-hull structure processed by a picosecond laser processing machine or a femtosecond laser processing machine.

The beneficial effects of the present invention mainly include: the present invention can be applied to devices having various surface forms on the workpiece surface and requiring waterproof and oil proof. Applying the invention to the surface of the window glass, the water droplets can roll down smoothly while taking away the dust on the surface of the window without leaving any traces, so that the window glass can be super-hydrophobic and self-cleaning, so that rain can be omitted on the car window The scraping avoids the trouble of frequent replacement due to the short life of the automobile wiper rubber strip; the invention is applied to the front and rear fenders of the automobile, and the lower part of the door, which can improve the front and rear fenders of the car body caused by the wheel throwing mud in rainy and snowy weather. And the situation that the lower part of the car door is easy to get dirty; applying the present invention to the surface of electronic products can ensure that it can work normally even if it accidentally falls into the water; applying the present invention to the surface of kitchen tiles and ventilation fan blades can prevent it from Contaminated with oil, which greatly reduces the trouble of cleaning.

All in all, the present invention can be bent and folded arbitrarily, and used on irregular surfaces to transform the original hydrophilic and lipophilic surfaces into superhydrophobic and oleophobic surfaces, and can be widely used in the fields of automobiles, kitchen utensils, and electronic products.

Description of drawings

Figure 1 is a cross-sectional view of the bowl-shaped secondary convex structure film

Figure 2 is a top view of a two-level convex structure film with a circular bottom

Figure 3 is a side view of the structure of the bowl-shaped secondary convex hull unit

Figure 4 is a top view of the structure of the bowl-shaped secondary convex hull unit

Among them: 1. Film layer 2. Adhesive coating R-the radius of the circumscribed circle of the bottom of the first-level convex hull r-the radius of the circumscribed circle of the bottom of the second-level convex hull L-the side length of the regular quadrilateral processing area H-the first-level convex hull shape The convex hull height of the structure h-the convex hull height of the second-level convex-hull structure d ₁ -the thickness of the film layer d ₂ -the thickness of the adhesive coating D-the distance between the first-level convex-hull structure units d-the second-level convex-hull structure interunit distance

Detailed ways

The present invention will be further described below in conjunction with specific examples.

Example 1 Automobile window wiper-free film

According to the requirements of the present invention, a bionic hydrophobic and oleophobic automotive window wiper-free film with anti-sticking function is designed. First of all, it is necessary to process the hot-pressing mold, which is made of metal oxide, and use a femtosecond laser to process the micro-modeling of bowl-shaped pits on its surface. The radius of the bottom circle of the first-level pit is 10um, the depth of the pit is 5um, and the distribution density of the pit is 100%. According to the calculation of the area occupancy ratio of the convex hull structure, the center distance between the structural units of the first-level pit is 20um. , the number of first-level pit units is 2500 on the processing surface with a format of 1mm x1mm. The radius of the bottom circle of the second-level pit is 1um, the depth of the pit is 0.5um, and the distribution density of the pit is 50%. According to the calculation of the area occupancy ratio of the convex hull structure, the center distance between the structural units of the second-level pit is calculated as 2.5um, the number of second-level pit units on the processed surface with a format of 1mm x1mm is 160,000. The polytetrafluoroethylene resin added with 6% fluorine-containing surfactant (FS) is molded, the thickness of the film layer is controlled to be 0.2 mm, and the polytetrafluoroethylene film with non-smooth surface morphology is obtained after cooling and peeling off. The smooth surface of the prepared polytetrafluoroethylene film is treated with argon plasma to increase the surface free energy of polytetrafluoroethylene to obtain a modified polytetrafluoroethylene film. Use a coater to coat a layer of non-marking adhesive with a thickness of 0.02mm. The water droplet is in contact with the surface of the film, and the water droplet presents a complete spherical shape, and the contact surface between the bottom of the water droplet and the film is very small. Use a contact angle measuring instrument to measure the macroscopic contact angle between the film and water to reach 168°-170°, and the rolling angle to reach 2°. When the film is slightly inclined, water droplets can roll freely on the surface of the film.

The car window wiper-free film processed according to the requirements of the present invention, under the premise of ensuring the driver's field of vision, the water droplets drip on the surface of the window glass, and can completely roll off without leaving traces while taking away the surface dust, so that it can be omitted. The installation of the car wiper avoids various problems caused by the wiper, ensures driving safety, and reduces car wind resistance and wind noise.

Embodiment 2 Automobile non-stick mud sticking film

According to the requirements of the present invention, a bionic hydrophobic and oleophobic car non-stick film with anti-stick function is designed. First of all, it is necessary to process the hot-pressing mold, which is made of gray cast iron, and use a picosecond laser to process the micro-morphology of hexagonal prism pits on its surface. The radius of the circumscribed circle of the regular hexagon at the bottom of the first-level pit is 80um, the depth of the pit is 50um, and the distribution density of the pit is 50%. According to the calculation of the area occupancy ratio of the convex hull structure, the distance between the structural units of the first-level pit is calculated. The center distance is 200um, and the number of pit units is 25 on the processing surface with a format of 1mmx1mm. The radius of the circumscribed circle of the regular hexagon at the bottom of the second-level pit is 5um, the depth of the pit is 3um, and the distribution density of the pit is 40%. According to the calculation of the area occupancy ratio of the convex hull structure, the distance between the structural units of the second-level pit is calculated. The center distance is 14um, and the number of pit units on the processing surface with a format of 1mm x1mm is 5100. The polytetrafluoroethylene resin added with 6% fluorine-containing surfactant (FS) is molded, the thickness of the film layer is controlled to be 0.3mm, and the polytetrafluoroethylene film with non-smooth surface morphology is obtained after cooling and peeling off. The smooth surface of the prepared polytetrafluoroethylene film is treated with nitrogen plasma to increase the surface free energy of polytetrafluoroethylene to obtain a modified polytetrafluoroethylene film. Use a coater to coat a layer of non-marking adhesive with a thickness of 0.03mm. The mud is in contact with the surface of the film, and the mud droplet presents a complete spherical shape, and the contact surface between the bottom of the mud droplet and the film is very small. Use a contact angle measuring instrument to measure the macroscopic contact angle between the film and water to reach 152°-155°, and the rolling angle to reach 3°. When the film is slightly inclined, the mud can roll freely on the surface of the film.

According to the requirements of the present invention, the non-stick film for automobiles can smoothly slide off the surface of the vehicle body due to the mud splashed by the wheels when the vehicle is running in rainy and snowy weather, without sticking to the surface of the vehicle body, so as to ensure the cleanliness of the vehicle body and greatly reduce car washing for car owners. trouble, saving water resources.

Claims (6)

1. A bionic anti-adhesive hydrophobic and oleophobic film is characterized in that it is made up of a film layer 1 and an adhesive coating 2, wherein the surface of the film layer 1 has a first-level convex-hull structure and a second-level convex-hull structure, and the convex-hull The structure is composed of convex hull structure units, the bottom of the convex hull structure unit is circular, regular triangle, regular quadrilateral or regular hexagonal; the convex hull is bowl-shaped, cylindrical, conical, triangular prism, quadrangular prism or hexagonal prism Type; film layer thickness d ₁ is 0.1-0.3mm, adhesive coating thickness d ₂ is 0.01-0.03mm. 2. The bionic anti-adhesive hydrophobic and oleophobic film according to claim 1 is characterized in that the first-level convex-hull structure and the second-level convex-hull structure, and its structural area occupancy rate represents the convex-hull structure at all levels The ratio of the sum of the areas of the circumscribed circles at the bottom to the surface area of the substrate is determined by the following formula: $\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; l</span>}}{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&pi;</span>}{\mathrm{<span\; class="notranslate">\; R</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; l</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; l</span>}}{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&pi;</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; l</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right.$ Among them: P ₁ represents the area occupancy of the first-level convex-hull structure; P ₂ represents the area occupancy of the second-level convex-hull structure; l represents the side length of the regular quadrilateral processing area; D represents the first-level convex-hull structure unit Distance; d represents the distance between the second-level convex hull structure units; R represents the radius of the circumscribed circle at the bottom of the first-level convex hull; r represents the radius of the circumscribed circle at the bottom of the second-level convex hull. 3. The bionic anti-adhesive hydrophobic and oleophobic film according to claim 1, characterized in that the convex hull height H of the first-level convex hull structure and the radius R of the circumscribed circle at the bottom of the convex hull are 10-100um, and the convex hull height H is 5-100um, and H≤R; the radius r of the circumscribed circle at the bottom of the convex hull of the second-stage convex hull structure is 1-10um, and the convex hull height h is 0.5-10um, and h≤r. 4. The bionic anti-adhesive hydrophobic and oleophobic film according to claim 1, characterized in that the area occupancy rate of the first-stage convex-hull structure P ₁ ≥ 10%, and the area occupancy rate of the second-level convex-hull structure P ₂ ≥30%. 5. The bionic anti-adhesive hydrophobic and oleophobic film according to claim 1, characterized in that the surface of the film layer with the first-level convex-hull structure and the second-level convex-hull structure is activated by adding 6% fluorine-containing surface The polytetrafluoroethylene resin of agent (FS) is formed by heat pressing through a mold. 6. The bionic anti-adhesive hydrophobic and oleophobic film according to claim 5, characterized in that the mold has a first-level convex hull structure and a first-level convex hull structure processed by a picosecond laser processing machine or a femtosecond laser processing machine. A non-smooth surface corresponding to a secondary convex hull structure.

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