CN113877785B - High-permeability hydrophobic dustproof thin film and preparation method thereof - Google Patents

Abstract

The invention discloses a high-permeability hydrophobic dustproof thin film and a preparation method thereof, and belongs to the technical field of functional material preparation. The invention solves the technical problems of high preparation cost, complex process and poor film binding force of the existing hydrophobic self-cleaning film. According to the invention, an atomic layer deposition system is utilized to prepare a layer of ZnO film on the surface of a glass substrate, then organic silicon resin and hydrophobic nano silicon dioxide are combined and spin-coated on the surface of a test piece, and the film with a good dust removal effect is obtained. The maximum light transmittance of the hydrophobic self-cleaning film prepared by the method reaches 98.12%, and the hydrophobic angle is 127 degrees. In addition, the coating also has the advantages of friction resistance, strong adhesive force, long service life and the like.

Description

A kind of high permeability hydrophobic dustproof film and preparation method thereof

technical field

The invention relates to a high permeability hydrophobic dustproof film and a preparation method thereof, belonging to the technical field of functional material preparation.

Background technique

The special environment of the moon makes it easy for moon dust to adhere to the surface of optical devices, which reduces the output power and easily causes the equipment to overheat and fail, which brings great harm to the lunar exploration project. The main sources of lunar dust are the weathering of the lunar surface and the collision of micrometeoroids. The lunar dust deposited on the surface of the lunar probe is difficult to be removed naturally due to its strong adhesion, which eventually leads to the failure or even failure of the lunar probe.

At present, the protection methods of moon dust are mainly divided into two types: active protection and passive protection. Among them, active protection is mainly to clean the protected surface or use external force to prevent moon dust from accumulating on the surface of the device. The commonly used methods include mechanical method and electrostatic precipitator method. In addition to dust removal brushes, mechanical methods include jet, ultrasonic, gel, viscose, etc. These methods all require the personal participation of astronauts or robots, wasting resources and time. However, the electrostatic precipitator method requires additional devices and control circuits, which increases the structural complexity of lunar exploration equipment and brings security risks. Different from active protection technology, passive technology can reduce the adsorption of moon dust on the surface of optical devices without external force. Surface modification of the device is usually performed before use to reduce the force between the dust and the protected surface for protection purposes.

As a passive dust removal technology, the hydrophobic self-cleaning film relies on micro-nano structure and low surface energy, and can take away a large amount of dust in the presence of water, but in the lunar environment, the dust removal effect of most hydrophobic self-cleaning films It is not ideal, and the low-surface-energy substances based on fluorocarbons have high cost, complicated preparation process and poor film adhesion. Therefore, from the perspective of improving the transparency and bonding force of the film, it is very necessary to provide a highly permeable hydrophobic dustproof film and a preparation method thereof.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned technical problems in the prior art, the present invention provides a high-permeability hydrophobic dustproof film and a preparation method thereof.

Technical scheme of the present invention:

A high-permeability hydrophobic dustproof film, the film uses a zinc oxide coating as a lower layer film, and a hydrophobic nano-silicon dioxide film as an upper layer film; the lower layer film is a single-layer zinc oxide coating with a thickness of 15-45nm ; The upper layer film is a single-layer hydrophobic nano-silicon dioxide film with a thickness of 100-300 nm.

Further limited, the particle size of the hydrophobic nano-silica is 10-30 nm.

The preparation method of the above-mentioned high permeability hydrophobic dustproof film, the method comprises the following steps:

Step 1, substrate pretreatment: ultrasonically clean the substrate;

Step 2, prepare the lower film layer: perform atomic layer deposition on the pre-treated substrate, and deposit a ZnO film layer on the surface of the substrate,

Step 3, preparing the upper film layer: spin-coating a coating containing hydrophobic nano-silica on the surface of the lower film layer, and post-processing is heated on a heating table at 80° C. for 5 minutes to obtain a high-permeability hydrophobic dust-proof film.

Further limited, the specific operation of ultrasonic cleaning in step 1 has been referred to as: first, use absolute ethanol to clean for 15 minutes, and the cleaning frequency is 1 time; then use acetone to clean for 20 minutes, and the cleaning frequency is 1 time; then use absolute ethanol to clean for 15 minutes, The number of cleanings was 2 times; then, deionized water was used for 15 minutes, and the number of cleanings was 1 time; then, anhydrous ethanol was used for 15 minutes, and the number of cleanings was 1 time; finally, it was dried at 70 °C for 1 hour.

To further define, the specific operation of the atomic layer deposition treatment in step 2 has been referred to as:

(1) Put the substrate processed in step 1 in the deposition chamber of the atomic layer deposition apparatus, pump the vacuum chamber to 4-6×10 ^-3 Torr, and then pass nitrogen gas until the chamber pressure is 0.1-0.2 Torr , keep the cavity temperature 100-200℃;

(2) Atomic layer periodic deposition growth is performed on the surface of the substrate, and 150-250 growth and deposition cycles are repeated to obtain a substrate coated with a ZnO film layer.

To be further defined, the process of each growth deposition cycle is:

①Inject the zinc source into the deposition chamber of the atomic layer deposition apparatus in the form of pulses, and the pulse time _t1 is 0.01-0.03s;

② Cut off the intake valve and exhaust valve to react, and the reaction time t ₂ is 5-8s;

③Open the intake valve and exhaust valve, and use nitrogen to purge, and the purge time _t3 is 30-50s;

④Inject the water source into the deposition chamber in the form of pulses, the temperature of the water source is room temperature, and the pulse time t ₄ is 0.01-0.03s;

⑤ Cut off the intake valve and exhaust valve to react, and the reaction time t5 is _5-8s to form ZnO;

⑥ Open the intake valve and exhaust valve, and use nitrogen to purge, the purge time t ₆ is 40s, and a deposition growth cycle is completed.

More specifically, the zinc source is diethylzinc.

Further limited, the spin coating conditions in step 3 are: rotational speed 3000 r/min, acceleration 1000 r/min, and time 30 s.

Further limited, the post-processing conditions in step 3 are: heating on a heating table at 80° C. for 5 min.

Further limited, the coating preparation process is:

① Fully disperse 0.5g of hydrophobic nano-silica particles into 50mL of ethanol solution to obtain a silica dispersion;

②Add 10 mL of silicone resin into 40 mL of ethanol solution to fully dissolve to obtain a silicone resin solution;

③ Take 5 mL of the silicone resin solution and add it to the silica dispersion obtained in step ①, and stir well to obtain a coating.

To be further limited, dispersing balls are used to enhance the dispersion effect of nano-silica.

The present invention has the following beneficial effects: the present invention firstly uses an atomic layer deposition system to prepare a layer of ZnO thin film on the surface of the glass substrate, then combines the silicone resin with the hydrophobic nano-silica, spin-coats it on the surface of the test piece, and obtains a dust-removing effect of the film. The present invention also has the following advantages:

(1) The present invention uses hydrophobic silica, which can achieve hydrophobic effect without fluorine modification compared to the prior art;

(2) The highest light transmittance of the film obtained by the present invention reaches 98.12%, and the hydrophobic angle is 127°. In addition, the film also has the advantages of friction resistance, strong adhesion, and long service life;

(3) The preparation method provided by the present invention has the advantages of simple process, readily available raw materials and low cost.

Description of drawings

Fig. 1 is the light transmittance at the wavelength of 400-800nm of the glass with the hydrophobic dustproof film made in Example 1;

Fig. 2 is an optical photograph of dripping water droplets on a glass substrate;

Fig. 3 is the optical photograph of dripping water droplets on the glass with the hydrophobic dustproof film made in Example 1;

Fig. 4 is an optical photograph of the contact angle of a water droplet on a glass substrate;

5 is an optical photo of the contact angle of glass water droplets with a hydrophobic dust-proof film prepared in Example 1;

6 is an optical picture of basalt powder sprinkled on a glass substrate and the glass with a hydrophobic dust-proof film made in Example 1 (the side near the angle ruler is the glass substrate);

Fig. 7 is the optical picture of the drop of basalt powder on the glass substrate and the glass with the hydrophobic dust-proof film obtained in Example 1 when the inclination angle is 50° (the side near the angle ruler is the glass substrate);

Figure 8 is an optical picture of the surface state of the glass substrate and the glass with a hydrophobic dust-proof film prepared in Example 1 after the basalt powder is dropped (the right side is the glass substrate);

9 is a schematic diagram of the test process of the hydrophobic dust-proof film bonding force and abrasion resistance obtained in Example 1;

Figure 10 is an optical photograph of the water contact angle of the film after rubbing the hydrophobic dust-proof film made in Example 1 once;

Figure 11 is an optical photograph of the water contact angle of the film after rubbing the hydrophobic dust-proof film prepared in Example 1 for 3 times;

Figure 12 is an optical photograph of the water contact angle of the film after rubbing 10 times of the hydrophobic dust-proof film made in Example 1;

Figure 13 is an optical photograph of the contact angle of the film water droplet prepared in Comparative Example 1;

Figure 14 is an optical photograph of the water contact angle of the film after rubbing the film prepared in Comparative Example 1 for 10 times;

Figure 15 is an optical photograph of the water contact angle in the edge region of the film after rubbing the film prepared in Comparative Example 1 for 10 times.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

The experimental methods used in the following examples are conventional methods unless otherwise specified. The used materials, reagents, methods and instruments, unless otherwise specified, are conventional materials, reagents, methods and instruments in the art, which can be obtained by those skilled in the art through commercial channels.

Example 1:

1. Substrate pretreatment

Ultrasonic cleaning of glass substrates:

First, use anhydrous ethanol to clean for 15 minutes, and the cleaning times are 1; then use acetone to clean for 20 minutes, and the cleaning times are once; then use anhydrous ethanol for 15 minutes, and the cleaning times are 2 times; then use deionized water for 15 minutes. The number of cleanings is 1 time; then use absolute ethanol to clean for 15min, and the number of cleanings is 1 time; finally, it is dried at 70°C for 1h.

2. Preparation of coating

(1) Preparation of the lower film layer:

The pre-treated glass substrate is subjected to atomic layer deposition, and a ZnO film is deposited on the surface of the glass substrate. The specific operation is called:

(1) Put the substrate processed in step 1 in the deposition chamber of the atomic layer deposition apparatus, pump the vacuum chamber to 5×10 ^-3 Torr, and then pass nitrogen gas until the chamber pressure is 0.15 Torr, and keep the chamber temperature 150℃;

(2) Atomic layer periodic deposition growth is performed on the surface of the substrate, and 180 growth deposition cycles are repeated to obtain a glass substrate coated with a ZnO film layer with a thickness of 30 nm;

The process of each growth deposition cycle is:

①Inject the zinc source into the deposition chamber of the atomic layer deposition apparatus in the form of pulses, and the pulse time t ₁ is 0.03s;

② Cut off the intake valve and exhaust valve to react, and the reaction time t ₂ is 6s;

③Open the intake valve and exhaust valve, and use nitrogen to purge, and the purge time _t3 is 40s;

④Inject the water source into the deposition chamber in the form of pulses, the temperature of the water source is room temperature, and the pulse time t ₄ is 0.03s;

⑤ Cut off the intake valve and exhaust valve to react, and the reaction time t ₅ is 6s to form ZnO;

⑥ Open the intake valve and exhaust valve, and use nitrogen to purge, the purge time t ₆ is 40s, and a deposition growth cycle is completed.

(2) Preparation of the upper film layer:

(1) Coating preparation: Disperse 0.5 g of hydrophobic nano-silica particles into 50 mL of ethanol solution under vigorous stirring, and use a dispersing ball to ensure that the nanoparticles are fully dispersed. Add 10 mL of silicone resin to 40 mL of ethanol solution to fully dissolve. Get 5mL of the silicone resin solution and add it to the silica dispersion, fully stir to obtain the coating;

(2) Spin coating the coating on the substrate coated with the ZnO film layer using a spin coater, the spin coating speed is 3000r/min, the acceleration is 1000r/min, the time is 30s, and the coating film thickness is 150nm. After the coating film is completed, it is obtained by post-processing Glass with hydrophobic dust film.

3. Performance characterization of the obtained glass with a hydrophobic dust-proof film:

(1) Transmittance test:

The glass with the hydrophobic dust-proof film obtained in Example 1 was tested with a UV-Vis spectrophotometer. The results are shown in Figure 1. The average light transmittance at the wavelength of 400-800 nm was 96.77% (the glass substrate was 100%), The highest light transmittance is 98.12%, and the test results show that the hydrophobic dustproof film prepared in the present application has high light transmittance and almost no change in surface transparency. This is due to the use of dispersing balls to enhance the dispersion effect of nano-silica and improve the light transmittance of the test piece.

(2) Hydrophobicity test:

After water droplets were dropped on the glass substrate and the glass with the hydrophobic dustproof film obtained in Example 1, the optical photos were shown in Figures 2 and 3. Comparing Figures 2 and 3, it can be seen that the hydrophobic dustproof film prepared in this example was obtained. It has a good hydrophobic effect. The measurement results using a contact angle tester are shown in Figures 4 and 5. The hydrophobic angle of the glass substrate is 27°, and the hydrophobic angle of the glass with a hydrophobic dust-proof film obtained in Example 1 is increased to 127°, It is further illustrated that the hydrophobic dustproof film prepared in this example has a good hydrophobic effect.

(3) Dust removal test:

Sprinkle a layer of basalt powder with a weight of about 0.2g on the glass substrate and the glass surface with the hydrophobic dustproof film obtained in Example 1 to simulate moon dust, and place it on the angle ruler, as shown in Figure 6, where the side near the angle ruler It is a glass substrate, and the glass with a hydrophobic dust-proof film is on the side away from the angle scale. When the inclination angle is about 50°, the basalt powder on the glass surface with the hydrophobic dust-proof film completely falls, but the basalt powder does not fall on the surface of the glass substrate, as shown in Figure 7 shown. After the dust removal test, the surface state of the glass substrate and the hydrophobic dustproof film prepared in Example 1 is shown in Figure 8. In the figure, the side close to the angle ruler is the glass substrate, and the side away from the angle ruler is the glass with the hydrophobic dustproof film. 8 It can be seen that the surface state of the glass with the hydrophobic dustproof film after dust removal is almost the same as that of the original test piece.

(4) Film adhesion and wear resistance test:

The test method is shown in Figure 9, by adding a 100g weight to the glass on the back of the film layer, sticking tape on the glass surface for dragging the sample, then with the film layer facing down, drag it on 240-grit sandpaper for 20cm, and finally In order to reduce the experimental error, the water contact angle will be tested 5 times in different areas of the sample to take the middle value as the evaluation standard. After rubbing for one time, the water contact angle is shown in Figure 10. The water contact angle of the coating decreases from 127° to 125°, and the hydrophobicity of the surface does not change significantly; after the third rubbing, the water contact angle is shown in Figure 11. shows that the water contact angle is reduced to 123°, which can still ensure high hydrophobicity; after rubbing for 10 times, the water contact angle is shown in Figure 12, the water contact angle is reduced to 113°, and there are small scratches on the surface. Scratches lead to a decrease in the hydrophobicity of the coating.

Comparative Example 1:

The difference between this comparative example and Example 1 is that the upper film layer is directly prepared on the pre-treated glass substrate to obtain a film without the lower film layer. The hydrophobicity test was carried out on the surface of the film obtained in this comparative example. The test results are shown in Figure 13, and the water contact angle is 123°. Comparing Figure 5 and Figure 13, it can be seen that whether there is an upper film layer has no effect on the water contact angle of the film. .

After 10 friction experiments, the water contact angle of the film obtained in this comparative example 1 is shown in Figure 14. The water contact angle is reduced from 127° to 89°. Due to the serious abrasion of the sandpaper in the edge area, the coating almost completely fails. The angle is shown in Figure 15, the water contact angle is only 56°, indicating that ALD acts as the middle layer, giving the glass a certain roughness, and mechanically interlocking with the upper silicon coating, which enhances the bonding force of the coating. Not easy to fall off in wear test.

Any modifications, equivalent replacements and improvements made within the principles shall be included within the protection scope of the present invention.

Claims (5)

1. a preparation method of a highly permeable hydrophobic dust-proof film, is characterized in that, The film uses a zinc oxide coating as the lower film, and a hydrophobic nano-silicon dioxide film as the upper film; the lower film is a single-layer zinc oxide coating with a thickness of 15-45 nm; the upper film is a single-layer film Hydrophobic nano-silica film with a thickness of 100-300nm; The method includes the following steps: Step 1, substrate pretreatment: ultrasonically clean the substrate; Step 2, prepare the lower film layer: perform atomic layer deposition on the pre-treated substrate, and deposit a ZnO film layer on the surface of the substrate, The specific operation process of the atomic layer deposition treatment in the described step 2 is: (1) Put the substrate processed in step 1 in the deposition chamber of the atomic layer deposition apparatus, pump the vacuum chamber to 4-6×10 ^-3 Torr, and then pass nitrogen gas to the chamber to 0.15 Torr to keep the chamber Temperature 100-200℃; (2) Atomic layer periodic deposition growth is performed on the surface of the substrate, and 150-250 growth and deposition cycles are repeatedly performed to obtain a substrate coated with a ZnO film layer; The process of each described growth deposition cycle is: ①Inject the zinc source into the deposition chamber of the atomic layer deposition apparatus in the form of pulses, and the pulse time _t1 is 0.01-0.03s; ② Cut off the intake valve and exhaust valve to react, and the reaction time t ₂ is 5-8s; ③Open the intake valve and exhaust valve, and use nitrogen to purge, and the purge time _t3 is 30-50s; ④Inject the water source into the deposition chamber in the form of pulses, the temperature of the water source is room temperature, and the pulse time t ₄ is 0.01-0.03s; ⑤ Cut off the intake valve and exhaust valve to react, and the reaction time t5 is _5-8s to form ZnO; ⑥ Open the intake valve and exhaust valve, use nitrogen to purge, the purge time t ₆ is 40s, and a deposition growth cycle is completed; Step 3, preparing the upper film layer: spin-coating a coating containing hydrophobic nano-silica on the surface of the lower film layer, and post-processing is heated on a heating table at 80° C. for 5 minutes to obtain a highly permeable hydrophobic dust-proof film; Described coating preparation process is: ① Fully disperse 0.5g of hydrophobic nano-silica particles into 50mL of ethanol solution to obtain a silica dispersion; ②Add 10 mL of silicone resin into 40 mL of ethanol solution to fully dissolve to obtain a silicone resin solution; ③ Take 5 mL of the silicone resin solution and add it to the silica dispersion obtained in step ①, and stir well to obtain a coating. 2 . The method for preparing a highly permeable hydrophobic dustproof film according to claim 1 , wherein the particle size of the hydrophobic nano-silica is 10-30 nm. 3 . 3. the preparation method of a kind of high-permeability hydrophobic dust-proof film according to claim 1, is characterized in that, the concrete operation of ultrasonic cleaning in described step 1 is called: at first use dehydrated alcohol to clean 15min, cleaning times 1 time; then use acetone to clean for 20 minutes, and the number of cleanings is 1 time; then use absolute ethanol for 15 minutes, and the number of cleaning times is 2 times; then use deionized water for 15 minutes, and the number of cleaning times is 1 time; then use no Washed with water ethanol for 15 min, the number of times of washing was 1; finally, it was dried at 70 °C for 1 h. 4. the preparation method of a kind of high permeability hydrophobic dustproof film according to claim 1, is characterized in that, described zinc source is diethyl zinc. 5 . The method for preparing a highly permeable and hydrophobic dustproof film according to claim 1 , wherein the spin coating conditions in the step 3 are: rotational speed 3000r/min, acceleration 1000r/min, and time 30s. 6 .

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