CN109987578A - A method for constructing a single concave structure on the surface of a micropillar - Google Patents

Abstract

The invention discloses a method for constructing a single concave structure on the surface of a micro-pillar, comprising the following steps: a. preparing a surface of a micro-pillar structure on at least one side of a substrate for standby use; b. preparing a surface of a silica gel film on one side of another substrate for standby use; c. Fully contact the surface of the silica gel film with the surface of the micro-pillar structure, peel off and then cure to obtain a micro single concave structure. The preparation method of the present invention is simple, does not require complicated and expensive equipment, and has strong universality. It has excellent droplet repelling function, and also has excellent properties such as oil resistance, anti-adhesion, and drag reduction.

Description

A method for constructing a single concave structure on the surface of a micropillar

technical field

The invention belongs to the technical field of material synthesis, and in particular relates to a method for constructing a single concave structure on the surface of a micro-pillar.

Background technique

In the field of surface and interface infiltration, the so-called single concave structure is also called T-shaped structure or mushroom head structure, that is, there is a corner between the top and bottom of the structure. When the droplet is placed on the surface of the structure, the liquid surface presents a suspended concave structure. instead of being stuck in a pit. Therefore, the rough surface with micro-concave structure often has a good function of repelling droplets, thereby realizing applications such as self-cleaning, anti-fouling, anti-adhesion, and drag reduction. For example, a single concave structure with self-cleaning effect can be applied to windows, glass, display screens, solar power generation panels, protective glasses, etc.; a single concave structure with drag reduction effect can be applied to microfluidic pipelines to accelerate pipeline transportation Energy saving; single concave structure with anti-adhesion effect can be applied to textiles, etc.

In recent years, due to the development of photolithography and 3D printing technology, the preparation of special micro/nanostructures has been achieved by means of micro/nanofabrication. For example, a double concave structure is prepared on a silicon wafer substrate by wet etching and multiple ion etching, and a single concave structure is obtained by 3D printing using a photosensitive epoxy resin. However, most of the existing preparation methods have cumbersome processes, complicated operations, high cost, and cannot achieve large-area preparation, and the selection of substrates is single and not universal.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for constructing a single concave structure on the surface of a micro-column, aiming at the deficiencies of the above-mentioned prior art. The single concave structure has excellent droplet repelling function. At the same time, it also has excellent properties such as oil resistance, anti-adhesion and drag reduction.

The technical scheme adopted in the present invention is: a method for constructing a single concave structure on the surface of a micro-pillar, comprising the following steps:

a. Prepare the surface of the micro-pillar structure on at least one side of the substrate for later use;

b. Prepare the surface of the silica gel film on one side of the other substrate for use;

c. Fully contact the surface of the silica gel film with the surface of the micro-pillar structure, peel off and then cure to obtain a micro-single concave structure.

In one embodiment, in step a, the diameter of the micro-pillars on the surface of the micro-pillar structure is 5 μm-100 μm.

In one embodiment, in step a, the preparation of the surface of the micro-pillar structure is as follows:

The micro-pillar structure is prepared by photolithography or surface replication, and the surface of the micro-pillar structure is activated by oxygen plasma for 15 minutes and then subjected to fluorination treatment.

In one of the embodiments, the surface of the micro-pillar structure is prepared by photolithography, as follows:

The surface of the micro-pillar structure is prepared by spin-coating the negative photoresist on the surface of the substrate, or the surface of the micro-pillar structure is prepared by etching the surface of the substrate through an etching mask.

In one embodiment, the surface of the micro-pillar structure is prepared by surface replication, as follows:

Pour the silica gel solution into the cylindrical pit model set on the surface of the substrate, place it horizontally for 10min-20min, put it in an oven with a temperature of 65℃ for 5h, and peel it off from the cylindrical pit model after the silica gel solution is completely cured. The micro-pillar structure surface can be obtained.

In one of the embodiments, the fluorination treatment is as follows:

Put the surface of the micro-pillar structure into a vacuum desiccator equipped with 100 μL of fluorinated reagent, and react for 2 h under the conditions of vacuum degree of 0MPa-0.95MPa and temperature of 20℃-30℃.

In one embodiment, the fluorination reagent is perfluorooctyltrichlorosilane, perfluoroquinyltrichlorosilane, perfluorooctyldimethylchlorosilane, perfluorooctyltriethoxysilane, perfluorooctyltriethoxysilane, One of fluorooctanoyl chloride or hexadecyl trichlorosilane.

In one embodiment, in step b, the surface of the silica gel film is prepared, as follows:

Drop 1 mL of the silica gel solution on a 24 mm × 60 mm rectangular cover glass and spin the silica gel solution by a spin coater to obtain the obtained silica film with a thickness smaller than the height of the micro-column.

In one embodiment, in step c, a single concave structure is obtained, as follows:

Put the surface of the fluorinated micro-column structure upside down on the surface of the silica gel film, press gently with your hands for 5 minutes to peel off the substrate on the surface of the silica gel film, invert the surface of the micro-column structure with the silica gel film attached, and put it in a temperature of 65 ℃. After baking in an oven for 5 hours, the film was completely cross-linked and cured to obtain a micro single concave structure.

In one embodiment, the silica gel solution is prepared by uniformly mixing the polydimethylsiloxane prepolymer and the crosslinking agent in a mass ratio of 10:1, and then removing bubbles by vacuum.

The beneficial effects of the invention are that the preparation method is simple, does not require complicated and expensive equipment, and has strong universality. The single concave structure has excellent droplet repelling function. At the same time, it also has excellent properties such as oil resistance, anti-adhesion and drag reduction.

Description of drawings

Fig. 1 is the preparation flow chart of the present invention.

Fig. 2 is a schematic diagram of a micro-column structure enlarged 950 times in Example 1;

3 is a schematic diagram of a single concave structure enlarged 950 times in Example 1;

Figure 4 is a schematic diagram of a micro-column structure magnified 860 times in Example 2;

Figure 5 is a schematic diagram of a single concave structure magnified 860 times in Example 2;

FIG. 6 is a schematic diagram of the contact angle of water droplets on the single concave structure in Example 2. FIG.

Detailed ways

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

Example 1:

As shown in Figure 1-Figure 3, the technical scheme adopted in the present invention is: a method for constructing a single concave structure on the surface of a micro-pillar, comprising the following steps:

Step 1. Prepare the surface of the micro-column structure by spin-coating the negative photoresist on at least one side of the substrate. After activating the surface of the micro-column structure by oxygen plasma for 15min, put it into a solution containing 100 μL of perfluorooctyl trimethylbenzene. In the vacuum dryer of chlorosilane, the reaction is carried out under the conditions of vacuum degree of 0MPa-0.95MPa and temperature of 20℃-30℃ for 2 hours, to obtain a micro-pillar structure surface with a diameter of 10μm and a height of 35μm;

Step 2: After the polydimethylsiloxane prepolymer and the cross-linking agent are uniformly mixed in a mass ratio of 10:1, remove air bubbles by vacuum, and drop 1 mL of the silica gel solution on a 24mm×60mm rectangular cover glass. After spinning at 12,000 rpm for 30 seconds, a silicone film was obtained;

Step 3: Place the surface of the fluorinated micro-column structure upside down on the surface of the silica gel film, and gently press with your hands for 5 minutes to peel off the substrate on the surface of the silica gel film. After inverting the surface of the micro-column structure with the silica gel film, put it at a temperature of After baking in an oven at 65°C for 5 hours, the film was completely cross-linked and cured to obtain a single concave structure, and a micro single concave structure with a diameter of 15 μm and a height of 45 μm was obtained.

Example 2:

As shown in Figure 1, Figure 4, Figure 5 and Figure 6, the technical solution adopted in the present invention is: a method for constructing a single concave structure on the surface of a micro-pillar, comprising the following steps:

Step 1. Prepare the surface of the micro-pillar structure by spin-coating the negative photoresist on the surface of the substrate. After activating the surface of the micro-pillar structure by oxygen plasma for 15 minutes, put it into a vacuum drying chamber containing 100 μL of perfluorooctyl trichlorosilane. In the reactor, the reaction was carried out under the conditions of vacuum degree of 0MPa-0.95MPa and temperature of 20℃-30℃ for 2 hours, to obtain a micro-pillar structure surface with a diameter of 25μm and a height of 45μm;

Step 2: After the polydimethylsiloxane prepolymer and the cross-linking agent are uniformly mixed in a mass ratio of 10:1, remove air bubbles by vacuum, and drop 1 mL of the silica gel solution on a 24mm×60mm rectangular cover glass. After spinning at 11,000 rpm for 30 seconds, the surface of the silicone film was obtained;

Step 3: Place the surface of the fluorinated micro-column structure upside down on the surface of the silica gel film, and gently press with your hands for 5 minutes to peel off the substrate on the surface of the silica gel film. After inverting the surface of the micro-column structure with the silica gel film, put it at a temperature of After baking in an oven at 65°C for 5 hours, a single concave structure was obtained after the film was completely cross-linked and cured, and a micro single concave structure with a diameter of 30 μm and a height of 60 μm was obtained.

Example 3:

As shown in Figure 1, the technical solution adopted in the present invention is: a method for constructing a single concave structure on the surface of a micro-pillar, comprising the following steps:

Step 1. After the polydimethylsiloxane prepolymer and the crosslinking agent are uniformly mixed in a mass ratio of 10:1, the bubbles are removed by vacuum, and then poured into the cylindrical pit model set on the surface of the substrate, and placed horizontally. After 20 minutes, put it in an oven with a temperature of 65 °C for 5 hours. After the silica gel solution is completely cured, peel it off from the cylindrical pit model to obtain a micro-pillar structure. After activating the surface of the micro-pillar structure by oxygen plasma for 15 minutes, Put it into a vacuum desiccator filled with 100 μL of perfluorooctyltrichlorosilane, and react for 2 h under the conditions of a vacuum degree of 0MPa-0.95MPa and a temperature of 20°C-30°C to obtain a diameter of 10 μm and a height of 35 μm. the surface of the micro-pillar structure;

Step 2: After the polydimethylsiloxane prepolymer and the cross-linking agent are uniformly mixed in a mass ratio of 10:1, remove air bubbles by vacuum, and drop 1 mL of the silica gel solution on a 24mm×60mm rectangular cover glass. After rotating at a speed of 12000 rpm for 30 seconds, the surface of the silicone film was obtained;

Step 3: Place the surface of the fluorinated micro-column structure upside down on the surface of the silica gel film, and gently press with your hands for 5 minutes to peel off the substrate on the surface of the silica gel film. After inverting the surface of the micro-column structure with the silica gel film, put it at a temperature of After baking in an oven at 65°C for 5 hours, the film was completely cross-linked and cured to obtain a single concave structure, and a micro single concave structure with a diameter of 15 μm and a height of 45 μm was obtained.

In Embodiment 1 and Embodiment 2, the negative photoresist is SU-8 negative photoresist. The surface of the micro-pillar structure is prepared by photolithography, including the preparation of the surface of the micro-pillar structure by spin-coating the negative photoresist on the surface of the substrate or the preparation of the surface of the micro-pillar structure by etching the surface of the substrate by an etching mask. Among them, the surface of the micro-pillar structure is prepared by spin-coating the negative photoresist on the surface of the substrate. The specific steps are: uniform glue (the rotation speed is 3000 rpm, and the time is 30 seconds), pre-baking (65 ℃ for 5 minutes, 95 ℃ for 10 minutes) ), exposure (the diameter of the circle in the mask is 10μm, exposure for 40 seconds at 5.5mw/ ^cm2 power), post-baking (65°C for 5min, 95°C for 10min), development and hardening (150°C for 15 minutes) ) and other steps to obtain a micro-column structure. The surface of the micro-pillar structure is prepared by etching the surface of the substrate through an etching mask, specifically, a photoresist pattern is prepared on the silicon substrate by a conventional photolithography process as an etching mask, and then a piranha solution (concentrated sulfuric acid and 35 % hydrogen peroxide mixed in a volume ratio of 7:3) and etching the silicon substrate with a photoresist pattern at 90° C. for 8h, the surface of the micro-pillar structure can be obtained. The above method is the prior art, and will not be described in detail in this application.

As shown in Figure 1, in the above three embodiments, when preparing a single concave structure, the surface of the prepared micro-column structure is placed upside down, and the surface of the silica gel film is placed upside down, so that the micro-column and the silica gel film on the surface of the micro-column structure are placed upside down. The silica film on the surface is in contact, while the surface of the micro-pillar structure and the substrate on the surface of the silica film are located at the top and bottom, respectively. By pressing, peeling and curing, a micro single concave structure can be obtained.

The above-mentioned embodiments only represent specific embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention.

Claims (10)

1. a kind of method for constructing single concave inward structure on micro-column sublist face, which comprises the following steps:

A, spare for miniature pillar structure surface in at least one of wheat flour of substrate；

B, wherein to prepare silica gel thin film surface on one side in another substrate spare；

C, silica gel thin film surface and miniature pillar structure surface are come into full contact with, is solidified after removing, miniature single concave inward structure is made.

2. a kind of method for constructing single concave inward structure on micro-column sublist face according to claim 1, which is characterized in that In step a, 5 μm -100 μm of miniature pillar diameter of the miniature pillar structure surface.

3. a kind of method for constructing single concave inward structure on micro-column sublist face according to claim 1, which is characterized in that It is described to prepare miniature pillar structure surface in step a, specific as follows:

Miniature pillar structure is made by photoetching or surface replica, miniature pillar structure surface is activated by oxygen gas plasma Fluorination treatment is carried out after 15min.

4. a kind of method for constructing single concave inward structure on micro-column sublist face according to claim 3, which is characterized in that It is specific as follows by optical graving for miniature pillar structure surface:

Miniature pillar structure surface is prepared or by etch mask in substrate surface in substrate surface spin coating by negative photoresist Etching prepares miniature pillar structure surface.

5. a kind of method for constructing single concave inward structure on micro-column sublist face according to claim 3, which is characterized in that Miniature pillar structure surface is prepared by surface replica, specific as follows:

Silica gel solution is poured into and is set in the cylinder pit model of substrate surface, after being horizontally arranged 10min-20min, is put into temperature Degree it can be obtained with the removing of cylinder pit model after silica gel solution is fully cured miniature to toast 5h in 65 DEG C of baking oven Pillar structure surface.

6. a kind of method for constructing single concave inward structure on micro-column sublist face according to claim 3, which is characterized in that The fluorination treatment, specific as follows:

Miniature pillar structure surface is put into the vacuum desiccator equipped with 100 μ L fluorination reagents, is 0MPa- in vacuum degree 0.95MPa and temperature react 2h under conditions of being 20 DEG C -30 DEG C.

7. a kind of method for constructing single concave inward structure on micro-column sublist face according to claim 6, which is characterized in that The fluorination reagent is that perfluoro capryl trichlorosilane, perfluor Kui base trichlorosilane, perfluoro capryl dimethylchlorosilane, perfluor are pungent Ethyl triethoxy silicane alkane, perfluorooctane chloride or hexadecyl trichlorosilane are one of.

8. a kind of method for constructing single concave inward structure on micro-column sublist face according to claim 7, which is characterized in that In step b, silica gel thin film surface is prepared, specific as follows:

The silica gel solution of 1mL is dripped on the rectangle coverslip of 24mm × 60mm and is obtained by spin coating instrument spin coating silica gel solution, Obtained silica gel thin film thickness is less than the height of miniature pillar.

9. a kind of method for constructing single concave inward structure on micro-column sublist face according to claim 1, which is characterized in that In step c, list concave inward structure is made, specific as follows:

The miniature pillar structure surface being fluorinated is placed upside down in right above silica gel thin film surface, is removed after pressing lightly on 5min with hand The substrate on silica gel thin film surface after being inverted the miniature pillar structure surface for being stained with silica gel thin film, is put into the baking that temperature is 65 DEG C 5h is toasted in case, and miniature single concave inward structure is made after making the fully crosslinked solidification of film.

10. a kind of method for constructing single concave inward structure on micro-column sublist face, feature according to claim 5 or 8 Be, the silica gel solution by polydimethylsiloxane prepolymer object and crosslinking agent by 10:1 mass ratio after mixing, lead to It is made after crossing the cleared bubble of vacuum.