CN111688189B - Method for preparing structural color three-dimensional array pattern based on sessile liquid drops - Google Patents

Abstract

The invention discloses a method for preparing a three-dimensional array pattern of structural colors based on sessile droplets, which mainly combines a multi-axis mechanical arm positioning and an automatic continuous ink supply system and adopts a method of colloidal particle assembly and gel curing to deposit the three-dimensional array pattern of structural colors with controllable appearance and adjustable layer number on a hydrophilic-hydrophobic patterned substrate. The method can realize the formation of the sessile liquid drops, ensure the uniform distribution of the printing ink on the substrate, and simultaneously, the liquid drops can be deposited for many times in the vertical direction, thereby realizing the construction of a multilayer structure. The method for preparing the structural color three-dimensional array pattern has the advantages of simple process, random design of microarray pixel point shape, strong pattern adjustability, uniform color, good repeatability and the like, and simultaneously, the multi-color pattern display can be realized by using a plurality of colloidal inks in parallel, and the construction of an optical coding array with a multilayer structure can also be realized.

Description

Method for fabricating structural color three-dimensional array patterns based on sessile droplets

technical field

The invention relates to a method for patterning a structural color material, in particular to a method for preparing a three-dimensional array pattern of structural color based on sessile droplets.

Background technique

Different from chemical colors such as dyes and pigments, physical colors, also known as structural colors, are the colors produced by the ordered micro-nano structure of materials scattered, diffracted or interfered with light of different wavelengths. It has the advantages of no fading, etc., and has a wide range of application prospects in the fields of sensing, display and anti-counterfeiting labels. Among them, the use of colloidal particle self-assembly to prepare photonic crystals with opal structure or one-dimensional structure is a relatively economical method for preparing structural color materials.

In recent years, patterning strategies for various structural color materials have been successively developed, which has greatly promoted their application in various components. For example, structural color patterns with various topographical features can be constructed by introducing structural color materials into prefabricated template grooves. However, this method has relatively complicated steps, a long preparation period, and the pattern is subject to a relatively expensive template structure, so it cannot meet the needs of arbitrary customization and mass production. Photolithography is an effective way to achieve high-precision structural color patterns, but this method also has problems such as expensive equipment required and a long pattern preparation cycle. Based on this Chinese patent CN104044380A discloses a method for preparing continuous photonic crystal patterns by inkjet printing. By controlling the adjacent interval time of the continuous inkjet ink droplets ejected, continuous photonic crystal lines are prepared, and the continuous photonic crystal pattern is realized. Simple and easy to scale preparation. Although the inkjet printing process is fast and efficient, it has high requirements on the ink, which requires high surface tension and low viscosity, and also has certain requirements on the printing substrate to overcome the coffee ring effect. 3D printing technology is an efficient method for constructing three-dimensional structural color materials developed in recent years. For example, Chinese patent CN106042377A discloses a method of adding structural color coatings to products based on 3D printing. Color printing ink has less material and poor pattern saturation, which limits its large-scale application.

SUMMARY OF THE INVENTION

Purpose of the invention: The purpose of the present invention is to provide a method for preparing a three-dimensional array pattern of structural color based on sessile droplets, so as to solve the problems of poor pattern designability, poor stability of droplet pixel points, cumbersome process, and inability to display colorfully in the existing method. And the problem of uncontrollable deposition liquid form and structure.

Technical solution: The method for preparing structural color three-dimensional array patterns based on sessile droplets described in the present invention includes the following steps:

(1) Preparation of a printing substrate with hydrophobic-hydrophilic arrayed micropatterns;

(2) The ink containing the monodisperse colloidal particles and the polymer precursor is delivered to the print head through the continuous ink supply device, and the print head is controlled by the multi-axis robotic arm to construct the monodisperse colloidal particles and the polymer monomer at the local preset position of the substrate. sessile droplet lattice of the body;

(3) The sessile droplet lattice is cured by chemical cross-linking, and the colloidal particles in the droplets are arranged in an orderly manner by volatilization self-assembly or external field-induced self-assembly to form a structural color pattern.

Wherein, the step (1) is specifically: using a mask method to perform plasma treatment or ozone treatment on the hydrophobic substrate to introduce a hydrophilic pattern, or to perform laser ablation and oxidation on a local position of the hydrophobic substrate to introduce a hydrophilic pattern.

In the step (2), the mass of monodisperse colloidal particles accounts for 0.01%-80% of the mass fraction of the solvent, the mass of the polymer monomer accounts for 1%-100% of the mass fraction of the solvent, and the solvent is water, ethylene glycol, dimethyl At least one of formamide and dimethyl sulfoxide.

In the step (2), the particle size of the monodisperse colloidal particles is 80nm-300nm, and the monodisperse colloid particles include any one of organic monodisperse colloid particles, inorganic monodisperse colloid particles or composite colloid particles.

The organic monodispersed colloidal particles are polystyrene colloidal particles or polymethyl methacrylate colloidal particles, the inorganic monodispersed colloidal particles are silicon dioxide, titanium dioxide, and ferric oxide colloidal particles, and the composite colloidal particles are wrapped in silicon dioxide Ferric oxide, polymethyl methacrylate wrapped polystyrene.

In the step (2), the polymer monomers are acrylamide, dimethyl acrylamide, isopropyl acrylamide, hydroxyethyl methyl acrylate, hyperbranched polyethylene glycol diacrylate modified by phenylboronic acid, polyethylene Alcohol, dextran, sulfhydryl or double bond functionalized gelatin, sulfhydryl or double bond functionalized sodium alginate, sulfhydryl or double bond functionalized hyaluronic acid, hyperbranched polyethylene glycol diacrylate and polyethylene glycol At least one of alcohol acrylates.

The step (2) is specifically: constructing a droplet dot matrix on a preset position of the printing substrate by means of a one-dimensional, two-dimensional or three-dimensional positioning and writing method of a 3D printing multi-axis mechanical arm.

The method for polymer crosslinking and curing in the step (3) is Michael addition reaction, light-initiated radical polymerization reaction or thermally-initiated radical polymerization reaction.

Beneficial effects: The present invention can effectively realize the uniform distribution of the colloidal dispersion on the substrate and form fixed droplets by utilizing the hydrophobic-hydrophilic effect, and combined with the continuous ink supply system and the mechanical arm device, can realize the construction of any droplet array pattern At the same time, the in-situ cured gel material is introduced into the droplet, which provides a flexible support for the colloidal assembly unit, effectively inhibits particle sedimentation, and ensures the stability and tunability of the structural color pattern; the entire process steps are simple and efficient. The low-cost equipment provides a new technical solution for the preparation of large-area structural color and colorful patterns, which has important application value in the fields of optical devices, sensors, and biological coding.

Description of drawings

1 is a schematic diagram of the fabrication process of a hydrophobic-hydrophilic array patterned substrate;

Figure 2 shows the test results of droplet adhesion ability of microdroplets in plasma treated and untreated areas;

Fig. 3 is the molecular formula of the raw material in embodiment 6;

Fig. 4 is the structural color material unit of different shapes;

Fig. 5 is the reflection spectrum diagram of structural color material;

6 is a schematic structural diagram of a microfluidic continuous ink supply device and a robotic arm automatic positioning device;

Figure 7 is a two-color structural color pattern prepared based on a fixed lattice;

Figure 8 is the preparation of a patterned array of multilayer structures.

Detailed ways

The present invention will be further described below with reference to the embodiments and accompanying drawings.

Example 1

(1) Preparation of structural color ink

Take 50 μL of the aqueous solution containing 0.1% silica-coated ferric oxide colloidal particles, dissolve 50 μL of 5% hyperbranched polyethylene glycol diacrylate in the above solution, adjust pH=9 and put it into the first syringe; take 100 μL 1% thiolated hyaluronic acid, adjust the pH of the mixture to 7.5, put it into the second syringe, place the two syringes on the ink supply device 1 of the microfluidic device, and inject the aqueous solution of the two syringes into the 3D through the ink supply device In the print head, the structural color ink is obtained by mixing.

(2) Preparation of hydrophobic-hydrophilic patterned printing substrates

As shown in Figure 1, the laser-punched paper was attached to the black silica gel plate by the method of masking, leaving only the micro-holes, and put it into an oxygen plasma device for processing. The processed position was hydrophilic, and the paper The covering part is hydrophobic, and the hydrophobic-hydrophilic patterned printing substrate can be obtained by removing the paper. By changing the pattern shape on the printing substrate, droplet arrays of different shapes can be obtained. It can be seen from Figure 2 that in the oxygen plasma When droplets were added to the surface after treatment, the droplets adhered to the surface, while the untreated surface maintained a hemispherical shape, indicating that the treated hydrophilic surface was easy to fix droplets and form droplet arrays.

(3) Preparation of patterned structural color materials

The above-mentioned structural color ink is extruded through the microfluidic device, the syringe is connected with the printing nozzle, and the multi-axis robotic arm 2 is used to control the printing nozzle to write the structural color ink in step (1) on the preset position of the printing substrate in real time. Controlling the action of the 3D printing nozzle can precisely control the spatial orientation of the structural color ink. Connecting the inks of different structural colors in parallel on the ink supply device can realize colorful printing in spatial positions. Under the condition of a magnetic field, multilayers with structural colors can be produced. Structure pattern.

Example 2

(1) Preparation of structural color ink

Take 100 μL of the aqueous solution containing 80% silica colloidal particles, dissolve 10% acrylamide and 1% N,N methylenebisacrylamide in the above solution, and put it into the first syringe after complete dissolution; 5% light The initiator 2959 was dissolved in 100 μL of water, and after it was completely dissolved, it was put into the second syringe. The aqueous solution of the two syringes was injected into the 3D printing nozzle through the ink supply device, and the structural color ink was obtained by mixing.

(2) Preparation of hydrophobic-hydrophilic patterned printing substrates

The patterned micropores were directly printed on the black silica gel plate by the laser etching method, the samples were placed in an oxygen plasma device for processing, and the film on the surface was peeled off to obtain a hydrophobic-hydrophilic patterned printing substrate.

(3) Preparation of patterned structural color materials

The ink supply device of the microfluidic device for the structural color ink is extruded into the printing nozzle, and the printing nozzle is controlled by a multi-axis mechanical arm to write the structural color ink in step (1) on the preset position of the printing substrate in real time. After curing, a multi-layer structure pattern with structural color is obtained.

Example 3:

(1) Preparation of structural color ink

Take 100 μL of an aqueous solution containing 0.01% polymethyl methacrylate colloidal particles, and dissolve 5% phenylboronic acid-modified hyperbranched polyethylene glycol diacrylate, 10% acrylamide, and 1% polyvinyl alcohol in the above mixed solution. , adjust the pH=8 of the mixed solution and put it into the first syringe; dissolve 5% photoinitiator in 100 μL of water, put it into the second syringe after it is completely dissolved, and inject the aqueous solution of the two syringes into the 3D printing nozzle through the ink supply device Inside, mix to make structural color ink.

(2) Preparation of hydrophobic-hydrophilic patterned printing substrates

The laser-punched paper is attached to the silica gel plate by the method of masking, leaving only the micropores, and is placed in oxygen plasma for treatment. The treated position is hydrophilic, and the untreated one is hydrophobic. Hydrophobic-hydrophilic patterned printing substrates can be produced.

(3) Preparation of patterned structural color materials

The ink supply device of the microfluidic device for the structural color ink is extruded into the printing nozzle, and the printing nozzle is controlled by a multi-axis mechanical arm to write the structural color ink in step (1) on the preset position of the printing substrate in real time. After curing, a multi-layer structure pattern with structural color is obtained.

Example 4:

(1) Preparation of structural color ink

Take 100 μL of an aqueous solution containing 10% polystyrene colloidal particles, dissolve 5% phenylboronic acid-modified hyperbranched polyethylene glycol diacrylate, 10% acrylamide, and 1% polyvinyl alcohol in the above mixed solution, adjust the mixing The solution pH=8 was put into the first syringe; 5% photoinitiator was dissolved in 100 μL of water, and after it was completely dissolved, it was put into the second syringe, and the aqueous solutions of the two syringes were injected into the 3D printing nozzle through the ink supply device, and mixed That is, the structural color ink is obtained.

(2) Preparation of hydrophobic-hydrophilic patterned printing substrates

Using the mask method, the laser-punched paper is attached to the silica gel plate, leaving only the micropores, and is placed in an oxygen plasma device for treatment. The treated position is hydrophilic, and the untreated one is hydrophobic. Hydrophobic-hydrophilic patterned printing substrates can be produced.

(3) Preparation of patterned structural color materials

The ink supply device of the microfluidic device for the structural color ink is extruded into the printing nozzle, and the printing nozzle is controlled by a multi-axis mechanical arm to write the structural color ink in step (1) on the preset position of the printing substrate in real time. After curing, a multi-layer structure pattern with structural color is obtained.

Example 5:

(1) Preparation of structural color ink

Take 100 μL of the aqueous solution containing 1% ferric oxide colloidal particles, dissolve 1% isopropylacrylamide and 0.1% N,N methylenebisacrylamide in the above mixed solution, and put it into the first syringe after it is completely dissolved Dissolve 5% potassium persulfate in 100 μL of water, put it into the second syringe after complete dissolution, inject the aqueous solution of the two syringes into the 3D printing nozzle through the ink supply device, and mix to obtain the structural color ink.

(2) Preparation of hydrophobic-hydrophilic patterned printing substrates

The laser-punched paper is attached to the silica gel plate by the method of masking, leaving only the micropores, and is placed in an oxygen plasma device for treatment. The treated position is hydrophilic, and the untreated one is hydrophobic. The hydrophobic-hydrophilic patterned printing substrate can be produced by removing the paper.

(3) Preparation of patterned structural color materials

Extruding the ink supply device of the microfluidic device for the structural color ink into the printing nozzle, and controlling the printing nozzle through a multi-axis robotic arm to write the structural color ink in step (1) on the preset position of the printing substrate in real time, that is, The uncured pattern is prepared, and the multilayer structure pattern with structural color can be prepared by placing it in a 60° C. oven under the condition of a magnetic field for curing and crosslinking.

Example 6:

(1) Preparation of structural color ink

Take 50 μL of a mixed solution of ethylene glycol and water containing 0.1% silica-coated ferric tetroxide colloidal particles, the mass concentration of ethylene glycol is 5%, and the rest is water. Dissolve 50 μL of 5% hyperbranched polyethylene glycol diacrylate in the above solution, adjust pH=9 and put it into the first syringe; take 100 μL of 2% thiolated hyaluronic acid, adjust the pH of the mixed solution to 7.5 and put it into the second syringe In the syringe, the aqueous solution of the two syringes is injected into the 3D printing nozzle through the ink supply device, and the structural color ink is obtained by mixing. The molecular formula of polyethylene glycol diacrylate combines photonic crystals with polymer monomers. Under alkaline conditions, the two polymer monomers can form a gel at room temperature through the Michael addition reaction of sulfhydryl groups and double bonds.

(2) Preparation of hydrophobic-hydrophilic patterned printing substrates

Use the mask method to attach the laser-punched paper to the silica gel plate, leaving only the micropores, and put it into an oxygen plasma device for treatment. The treated position is hydrophilic, and the untreated one is hydrophobic. Remove the paper The hydrophobic-hydrophilic patterned printing substrate can be prepared.

(3) Preparation of patterned structural color materials

The ink supply device of the microfluidic device for the structural color ink is extruded into the printing nozzle, and the printing nozzle is controlled by a multi-axis mechanical arm to write the structural color ink in step (1) on the preset position of the printing substrate in real time, and control the printing nozzle. The 3D printing nozzle can precisely control the spatial orientation of the structural color ink. Connecting inks of different structural colors in parallel on the ink supply device can achieve colorful printing in spatial positions. Finally, a multi-layer structure with structural colors can be produced under the condition of a magnetic field. pattern.

Figure 4 is a display unit made of different shapes of structural color gel materials by plasma treatment of paper punched by different lasers and positioning and writing by using a robotic arm. Fig. 5 is the spectrum of the prepared structural color material, the magnetic field intensity increases gradually from right to left, and it can be seen that different structural colors are displayed under different magnetic field intensities. The structural colors in the centrifuge tubes are red, green and blue from right to left. Figure 6 is a diagram of the experimental setup of the microfluidic continuous ink supply system and the multi-axis robotic arm automatic positioning system. The structural color material is combined with microfluidics, and the robotic arm is used to extrude droplets on the printing substrate for patterned positioning writing . Figure 7 shows a flower pattern with structural color, and the display of structural color is controlled by the presence or absence of an applied magnetic field. Figure 8 shows that by dropping different structural color ink droplets on the hydrophobic-hydrophilic micropatterned printing substrate, after curing and crosslinking, a three-dimensional array pattern of structural color with multiple layers is formed.

Claims (6)

1. A method for preparing structural color three-dimensional array patterns based on sessile droplets, characterized in that, comprising the following steps: (1) Preparation of printing substrates with hydrophobic-hydrophilic arrayed micropatterns. The printing substrates with hydrophobic-hydrophilic arrayed micropatterns are constructed in one of the following two ways: plasma treatment on the hydrophobic substrate using a mask method Or ozone treatment to introduce hydrophilic patterns, or laser ablation and oxidation at the local position of the hydrophobic substrate to introduce hydrophilic patterns; (2) The ink containing monodisperse colloidal particles and polymer precursors is delivered to the print head through a continuous ink supply device, and the print head is controlled by a multi-axis robotic arm to construct a monodisperse colloidal particle and a polymer monolayer at the local preset position of the substrate. The sessile droplet lattice of the body, the polymer monomer is acrylamide, hydroxyethyl methyl acrylate, phenylboronic acid modified hyperbranched polyethylene glycol diacrylate, polyvinyl alcohol, dextran, sulfhydryl or double bond function At least one of gelatin, sulfhydryl or double bond functionalized sodium alginate, sulfhydryl or double bond functionalized hyaluronic acid, hyperbranched polyethylene glycol diacrylate; (3) The sessile droplet lattice is cured by chemical cross-linking, and the colloidal particles in the droplet adopt volatile self-assembly or external field-induced self-assembly to realize the orderly arrangement of the colloidal particles and form a structural color pattern. 2 . The method for preparing structural color three-dimensional array patterns based on sessile droplets according to claim 1 , wherein in the step (2), the mass fraction of monodisperse colloidal particles accounts for 0.01%-80% of the solvent mass fraction, and the polymerization The mass of the precursor material accounts for 1%-100% of the solvent mass fraction, and the solvent is at least one of water, ethylene glycol, dimethylformamide, and dimethyl sulfoxide. 3. The method for preparing a structural color three-dimensional array pattern based on sessile droplets according to claim 1, wherein in the step (2), the particle size of the monodisperse colloidal particles is 80 nm-300 nm, and the The disperse colloid particles include any one of organic monodisperse colloid particles, inorganic monodisperse colloid particles or composite colloid particles. 4. The method for preparing a three-dimensional array pattern of structural color based on sessile droplets according to claim 3, wherein the organic monodisperse colloidal particles are polystyrene colloidal particles or polymethyl methacrylate colloidal particles, inorganic The monodisperse colloidal particles are silicon dioxide, titanium dioxide, and ferric tetroxide colloidal particles, and the composite colloidal particles are silica-wrapped ferric tetroxide and polymethyl methacrylate-wrapped polystyrene. The method for preparing a three-dimensional array pattern of structural colors based on sessile droplets according to claim 1, wherein the step (2) is specifically: one-dimensional, two-dimensional or three-dimensional by 3D printing a multi-axis robotic arm The method of positioning writing constructs a dot matrix of droplets on the predetermined position of the printing substrate. 6 . The method for preparing structural color three-dimensional array patterns based on sessile droplets according to claim 1 , wherein the chemical cross-linking and curing method in the step (3) is Michael addition reaction, photo-initiated radical polymerization Reaction or heat initiates free radical polymerization.

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