A method for regulating surface adhesion in both air and oil

Abstract

The present invention discloses a method for regulating surface adhesion in both air and oil, the method comprising the following steps: step 1, performing fluorosilane modification on a surface having a micro-nano structure that is responsive to ultraviolet light, and heating to make the fluorosilane more uniform on the surface; step 2, placing the surface modified with fluorosilane under ultraviolet light, and regulating the adhesion of the surface under air and oil by controlling the time of ultraviolet light exposure and the heating method. The preparation process of the present invention is simple, and the rough micro-nano structure on the surface can better show a super-hydrophobic effect, and can achieve surface adhesion control in a complex environment.

Description

Technical Field

[0001] The invention relates to a method for regulating surface adhesion, and in particular to a method for regulating surface adhesion both in air and oil. Background Art

[0002] Superhydrophobic surfaces with smart adhesion have important applications in microfluidic systems, material science, and biotechnology. Currently, research on the regulation of surface adhesion only occurs in a single environment, such as the regulation of the adhesion of water droplets in air. When performing micro-droplet reactions under air conditions, the loss of water droplets due to evaporation is often inevitable, but this defect is easily avoided in oil. Summary of the invention

[0003] In view of the above problems existing in the prior art, the present invention provides a method for regulating surface adhesion both in air and oil, and the method can achieve surface adhesion control in complex environments.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] A method for controlling surface adhesion in both air and oil, comprising the following steps:

[0006] Step 1: Perform fluorosilane modification on a surface having a micro-nano structure that is UV-responsive, and make the fluorosilane more uniform on the surface by heating, wherein:

[0007] The surface with micro-nano structure and ultraviolet light response is titanium dioxide;

[0008] The heating temperature is 90°C and the time is 15 to 25 minutes;

[0009] Step 2: Place the fluorosilane-modified surface under ultraviolet light, and adjust the adhesion of the surface under air and oil by controlling the ultraviolet light exposure time and heating method. The specific adhesion adjustment method is as follows:

[0010] (1) The fluorosilane-modified surface is placed in air and irradiated under ultraviolet light for 60 to 70 minutes to change its surface adhesion from a low adhesion state to a high adhesion state; heated at 100°C for 115 to 125 minutes to change its surface adhesion from a high adhesion state to a low adhesion state, thereby achieving the high-low adhesion transition of the surface in air;

[0011] (2) The fluorosilane-modified surface is placed in air and irradiated under ultraviolet light for 90 to 100 minutes, so that the adhesion of the surface under oil changes from a low adhesion state to a high adhesion state under oil; heated at 100°C for 55 to 65 minutes, the adhesion of the surface under oil changes from a high adhesion state to a low adhesion state, thereby achieving the high-low adhesion transition of the surface under oil;

[0012] The oil includes various alkanes including n-hexane and various organic solvents such as petroleum ether, benzene, gasoline, etc.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. The preparation process is simple and involves simple steps.

[0015] 2. The rough micro-nano structure on the surface can better show the superhydrophobic effect.

[0016] 3. The present invention can achieve surface adhesion regulation under both air and oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of ultra-low adhesion of water droplets in air;

[0018] Figure 2 Schematic diagram of ultra-low adhesion of water droplets under oil;

[0019] Figure 3 This is a diagram showing the high adhesion of water droplets in the air;

[0020] Figure 4 This is a diagram showing the high adhesion of water droplets under oil. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0022] The present invention provides a method for controlling the surface adhesion of water droplets both in air and oil, and the specific steps of the method are as follows:

[0023] Step 1: Cut a titanium sheet with a purity of 99.7%, and ultrasonically clean it in acetone, alcohol and distilled water in turn, and then chemically polish it in a mixed solution of HF, HNO3 and H2O (volume ratio = 1:4:5).

[0024] Step 2: Anodize the titanium sheet prepared in step 1. Anodize at room temperature in a two-electrode cell with a titanium sheet as a working electrode and a platinum sheet as a counter electrode at a voltage of 40 V for 3 hours to obtain a TiO2 nanofilm, which is then immediately rinsed with a large amount of deionized water and dried in air.

[0025] Step 3: Incubate the TiO2 nanofilm prepared in step 2 in air at 5°C min -1The annealing was carried out at 350 °C for 1 h with a heating rate of 1.5, and then maintained at 350 °C for 1 h, and then cooled.

[0026] Step 4: When the temperature reaches room temperature, the surface of the TiO2 film is further maintained at 150°C for about 1 hour and then cooled.

[0027] Step 5. The surface of the TiO2 film obtained in step 4 is vapor-phase modified with fluorosilane. The specific steps are as follows: Place the surface of the TiO2 film in a vacuum dryer, place two drops of fluorosilane in a watch glass, evacuate the film, place it for 12 hours, and then heat it at 90°C for 20 minutes.

[0028] Step 6: Place the fluorosilane-modified TiO2 film surface under ultraviolet light (18 mW / cm2), and control the ultraviolet light irradiation time and heating to achieve the regulation of the adhesion of the TiO2 film surface in air and oil (n-hexane). The specific regulation method is as follows:

[0029] (1) The fluorosilane-modified surface was placed in the air and irradiated under ultraviolet light for 65 minutes at room temperature, and its surface adhesion changed from a low adhesion state to a high adhesion state; when heated at 100°C for 120 minutes, its surface adhesion changed from a high adhesion state to a low adhesion state, thereby achieving the high-low adhesion transition of the surface in the air;

[0030] (2) The fluorosilane-modified surface was placed in air and irradiated with ultraviolet light at room temperature for 95 minutes, so that the surface adhesion under oil (n-hexane) changed from a low adhesion state to a high adhesion state; heated at 100°C for 60 minutes, the surface adhesion under oil changed from a high adhesion state to a low adhesion state under oil, thereby achieving a high-low adhesion transition of the surface under oil.

[0031] The above method prepares a nanostructured super-hydrophobic TiO2 nanotube film and demonstrates the intelligent control of surface adhesion in air and oil based on the light responsiveness of TiO2. Under ultraviolet light irradiation, TiO2 undergoes electron transitions to generate oxygen holes, thereby decomposing organic matter on the surface, and produces water molecules and hydroxyl groups to enhance the surface adhesion to water droplets. A super-hydrophobic surface is obtained by simple fluorosilane molecular modification, and a high-adhesion surface in air and oil environments is obtained by simple ultraviolet light irradiation. Ultraviolet irradiation can cause the surface adhesion to be transformed into a high-adhesion state in both air and oil, but the required ultraviolet irradiation time is different, and the high-low adhesion transition of the surface in air and oil is achieved by heating.

[0032] Depend on Figure 1 and Figure 2 It can be seen that the surface has low adhesion both in air and in n-hexane, and water droplets do not stick to the surface at all. Figure 3 and Figure 4 is the state of water droplets on the surface after UV irradiation for different time periods. Figure 3 and Figure 4 It can be seen that the water droplets become highly adherent on the surface after UV irradiation.

[0033] In addition to using TiO2 film as the surface, the present invention can also use other surfaces with ultraviolet light response such as zinc oxide, silicon dioxide, etc., and achieve the regulation of surface adhesion under oil and in the air through the method of fluorosilane modification and ultraviolet light irradiation.

Claims

1. A method for controlling surface adhesion in both air and oil, characterized in that The method comprises the following steps: Step 1: performing fluorosilane modification on a surface having a micro-nano structure that is UV-responsive, and making the fluorosilane more uniform on the surface by heating; Step 2: Place the fluorosilane-modified surface under ultraviolet light, and adjust the adhesion of the surface under air and oil by controlling the ultraviolet light exposure time and heating method. The adhesion adjustment method is as follows: (1) The fluorosilane-modified surface is placed in the air and irradiated under ultraviolet light for 60 to 70 minutes, so that the surface adhesion changes from a low adhesion state to a high adhesion state; heated at 100°C for 115 to 125 minutes, the surface adhesion changes from a high adhesion state to a low adhesion state, thereby achieving the high-low adhesion transition of the surface in the air; (2) The fluorosilane-modified surface is placed in air and irradiated with ultraviolet light for 90 to 100 minutes, so that the adhesion of the surface under the oil changes from a low adhesion state to a high adhesion state; heated at 100°C for 55 to 65 minutes, the adhesion of the surface under the oil changes from a high adhesion state to a low adhesion state, thereby achieving a high-low adhesion transition of the surface under the oil.

2. The method for controlling surface adhesion in both air and oil according to claim 1, characterized in that In the step 1, the surface having a micro-nano structure and having an ultraviolet light response is a titanium dioxide surface.

3. The method for controlling surface adhesion in air and oil according to claim 1, characterized in that In the step 1, the heating temperature is 90° C. and the heating time is 15 to 25 minutes.

4. The method for controlling surface adhesion in air and oil according to claim 1, characterized in that The oil is alkane, petroleum ether, benzene or gasoline.

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