Preparation method of durable super-hydrophobic carbon nanotube film composite material

Abstract

The application belongs to the field of super-hydrophobic material preparation, and particularly relates to a preparation method of a durable super-hydrophobic carbon nanotube film composite material. The application inserts a PDMS prefabricated layer between a carbon nanotube film substrate after plasma cleaning and a super-hydrophobic coating, and prepares a super-hydrophobic coating based on PDMS and SiO2 nanoparticles. In a heat curing cross-linking reaction, the SiO2 nanoparticles wrapped by PDMS are partially embedded in the incompletely cured PDMS prefabricated layer, and the prepared super-hydrophobic material exhibits excellent mechanical stability. The super-hydrophobic material realized by the method has low cost, does not need a complex processing process, can maintain the flexibility of the carbon nanotube film, expands the application field of the carbon nanotube film material, strengthens the basic research on the industrial application of the super-hydrophobic surface of the carbon nanomaterial, and meets higher application requirements.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of super-hydrophobic material preparation, and particularly relates to a preparation method of a durable super-hydrophobic carbon nanotube film composite material. BACKGROUND

[0002] In order to adapt to the rapid development of flexible and wearable electronic products or devices, lightweight, waterproof self-cleaning and other materials with outstanding novel properties are continuously developed. Building a super-hydrophobic coating on a carbon nanotube film is an important way to obtain a waterproof surface. However, due to the poor mechanical strength of the coating and the weak adhesion between the coating and the substrate, the super-hydrophobicity of the coating is easily lost under mechanical load. Chinese patent 201910753949.1 provides a preparation method of a conductive super-hydrophobic carbon nanotube / polymer flexible film, a thermoplastic elastomer TPE solution is sprayed on the upper surface of the carbon nanotube film, a polydimethylsiloxane hydrophobic layer is prepared on the lower surface by solidification, and a multi-layer carbon nanotube / polymer composite film is prepared by compounding with a silicone elastomer. Preparation and performance of SiO2 / PDMS composite transparent super-hydrophobic coating (New Chemical Materials, 2017, 45, 6:227-229) discloses that a silicone rubber solution is spin-coated on a glass substrate, then SiO2 dispersion liquid is spin-coated multiple times, and finally a SiO2 / PDMS composite coating is obtained by solidification. However, the material prepared by the above method only has a super-hydrophobic surface and cannot achieve the effect of wear resistance. The super-hydrophobic material on the surface can be easily damaged by the durability test. SUMMARY

[0003] The application provides a preparation method of a durable super-hydrophobic carbon nanotube film composite material, which expands the application of carbon nanotube films in the waterproof field, maintains the flexibility and mechanical properties of the carbon nanotube film, and can maintain good hydrophobicity under different curved surfaces and different environments.

[0004] The application provides a preparation method of a durable super-hydrophobic carbon nanotube film composite material with a simple process and extremely low cost, which comprises the following steps:

[0005] Step one: pretreat the carbon nanotube film substrate, place the long strip-shaped carbon nanotube film on a stainless steel plate and press it with a copper sheet to prevent it from being sucked in during vacuumization, and then place it in a plasma cleaning chamber for cleaning to remove surface impurities.

[0006] Preferably, the plasma cleaning power is 70 W, and the cleaning time is 120 s.

[0007] Step two: dissolve polydimethylsiloxane (PDMS) and a curing agent in n-hexane, and perform ultrasonic treatment to form a pre-prepared layer PDMS for bonding the carbon nanotube film substrate and the super-hydrophobic coating.

[0008] Preferably, the mass ratio of the PDMS to the curing agent is 10:1, and the ultrasonic treatment time is 30 min.

[0009] Step three: disperse the nanosilica particles in n-hexane, perform ultrasonic treatment, then add octadecyltrichlorosilane, and perform stirring in a normal temperature water bath to prepare solution A;

[0010] Preferably, the size of the nanosilica particles is 20±10 nm, the ultrasonic treatment time is 20 min, the mass ratio of the nanosilica to the octadecyltrichlorosilane is 8:5, and the water bath stirring time is 2 h.

[0011] Step four: weigh a proper amount of PDMS and a curing agent, dissolve them in the above solution A, perform ultrasonic treatment, and then perform magnetic stirring to prepare solution B.

[0012] Preferably, the mass ratio of the PDMS to the curing agent is 10:1, the ultrasonic treatment time is 30 min, and the magnetic stirring time is 2 h.

[0013] Step five: coat the prefabricated layer PDMS obtained in step two on the pretreated carbon nanotube film substrate to perform pre-solidification, then spray the solution B obtained in step four on the surface thereof, and place it in an oven to perform solidification, so that a durable superhydrophobic carbon nanotube film composite material is obtained.

[0014] Preferably, the pre-solidification temperature is 80℃, and the time is 20 min; and the solidification temperature is 100℃, and the time is 2 h.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] 1. The carbon nanotube composite film prepared by the present application has the lightweight flexibility and foldability of a film material, and can also maintain durable superhydrophobicity under mechanical deformation states such as bending and twisting.

[0017] 2. The preparation method provided by the present application is simple, low in cost, and short in preparation period.

[0018] 3. The present application expands the application field of carbon nanotube film materials in flexible electronic waterproofing, strengthens the basic research on the industrial application of superhydrophobic surfaces of carbon nanomaterials, and meets higher application requirements. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Figure 1 is a preparation process schematic diagram of the durable superhydrophobic carbon nanotube film composite material;

[0020] Figure 2 Figure 2 is a display diagram of the flexibility (a) and hydrophobicity (b) of the sample prepared in Example 1.

[0021] Figure 3 Sample physical comparison chart for the sample prepared for Example 1 and Comparative Example 1;

[0022] Figure 4 Adhesive tape peeling durability test chart for the sample prepared for Example 1;

[0023] Figure 5 Water washing experiment durability test chart for the sample prepared for Example 1;

[0024] Figure 6 Water drop experiment durability test chart for the sample prepared for Example 1;

[0025] Figure 7 Friction experiment comparison for the sample prepared for Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0026] The application will be further described in conjunction with the specific embodiments, but the scope of protection of the application is not limited to the content described.

[0027] Example 1

[0028] S1, pretreatment of the carbon nanotube film substrate: the long strip type carbon nanotube film was placed in a stainless steel tray, and a copper sheet was used to press it to prevent it from being sucked in during vacuumization. It was placed in a plasma cleaning chamber for cleaning, and the plasma cleaning power was 70 W, and the time was 120 s.

[0029] S2: 0.5 g of PDMS adhesive and 0.05 g of curing agent were dissolved in 4.5 g of n-hexane, and ultrasonic treatment was performed for 30 min to form a pre-prepared layer PDMS for bonding the substrate and the coating.

[0030] S3: 0.4 g of nano-silicon dioxide was dissolved in 12 ml of n-hexane, and ultrasonic treatment was performed for 20 min. 0.25 g of octadecyltrichlorosilane was added, and magnetic stirring was performed in a normal temperature water bath for 2 h, which was recorded as solution A.

[0031] S4: 1 g of PDMS and 0.1 g of curing agent were further dissolved in the above solution A, and ultrasonic treatment was performed for 30 min. Magnetic stirring was performed for 2 h. After the magnetic stirring was completed, solution B was obtained.

[0032] S5: The prepared pre-prepared layer PDMS was coated on the carbon nanotube film substrate for pre-curing, and the pre-curing temperature was 80°C, and the pre-curing time was 20 min. Then the above-mentioned solution B was sprayed on the surface, and was sent into an oven for curing, and the curing temperature was 100°C, and the curing time was 2 h. After the curing was completed, a durable super-hydrophobic carbon nanotube film composite material was obtained.

[0033] The surface contact angle of the durable super-hydrophobic carbon nanotube film composite material is 157° and the rolling angle is 0° after testing.

[0034] Comparative Example 1

[0035] S1, pretreatment of the carbon nanotube film substrate: the long strip-shaped carbon nanotube film was placed in a stainless steel tray, and a copper sheet was used to press it to prevent it from being sucked in during vacuumization. The film was placed in a plasma cleaning chamber for cleaning, with a plasma cleaning power of 70 W and a time of 120 s.

[0036] S2: 0.4 g of nano-silica was dissolved in 12 ml of n-hexane, ultrasonic treatment was performed for 20 min, 0.25 g of octadecyltrichlorosilane was added, and magnetic stirring was performed in a normal temperature water bath for 2 h, which was recorded as solution A.

[0037] S3: 1 g of PDMS and 0.1 g of curing agent were further dissolved in the above solution A, ultrasonic treatment was performed for 30 min, and magnetic stirring was performed for 2 h. After the magnetic stirring was completed, solution B was obtained.

[0038] S4: the above solution B was coated on the carbon nanotube film substrate for curing, with a curing temperature of 100°C and a curing time of 2 h. After curing was completed, the durable super-hydrophobic carbon nanotube film composite material was obtained.

[0039] Figure 3 The sample prepared in Example 1 and Comparative Example 1 were compared in the actual physical state, and it can be seen from the figure that the sample prepared in Comparative Example 1 had cracks on the surface and was easy to fall off because PDMS preformed layer was not added. The sample prepared in Example 1 had a smooth and flat surface because of the addition of the PDMS preformed layer, which adhered the surface particles together.

[0040] The durable super-hydrophobic carbon nanotube film composite material prepared in Example 1 was subjected to a tape peeling experiment. The specific method was that a constant force was applied to the sample by rolling a 200 g weight on the surface of a 3M tape. The contact angle and rolling angle of the super-hydrophobic coating were measured every 10 peeling cycles. The above operation was repeated 10 times to study the influence of tape peeling on the hydrophobicity of the super-hydrophobic coating. As shown in Figure 4 the contact angle of the super-hydrophobic coating decreased slightly, and the rolling angle increased significantly, indicating that the coating could still maintain high hydrophobicity after multiple tape peeling.

[0041] The durable super-hydrophobic carbon nanotube film prepared in Example 1 was subjected to a water washing experiment. The specific method was that 50 mL of deionized water was added to a 100 mL beaker, and 5 g of soap powder was added. The soap powder was completely dissolved in the deionized water by stirring with a glass rod. Subsequently, the prepared durable super-hydrophobic carbon nanotube film composite material was placed in the beaker containing the soap powder solution and subjected to magnetic stirring. As shown in Figure 5As shown, with the increase of washing time, the contact angle of the super-hydrophobic coating decreases slightly, and the rolling angle increases obviously, which indicates that the coating can still maintain high hydrophobicity after long time washing.

[0042] The water droplet experiment was conducted on the durable super-hydrophobic carbon nanotube film composite prepared in Example 1. Specifically, the durable super-hydrophobic carbon nanotube film composite was fixed on a glass slide, and the glass slide was placed at an angle of 30°, and water was dropped from a height of 30 cm at a speed of 3 drops / s. The durability of the super-hydrophobic coating was observed by measuring the change of the contact angle. Figure 6 As shown, after 5h of water flow scouring, the contact angle fluctuated around 1°, and after 8h of water flow scouring, the coating still maintained super-hydrophobicity, and the water droplets on the surface of the coating quickly detached from the surface of the coating.

[0043] To verify the friction resistance of the durable super-hydrophobic carbon nanotube film composite, a friction experiment was conducted. Sample A was the hydrophobic carbon nanotube film composite prepared in Comparative Example 1 without the addition of a PDMS preformed layer, and sample B was the durable super-hydrophobic carbon nanotube film composite prepared in Example 1 with the addition of a preformed layer of PDMS. Specifically, a 100g weight was used to press the glass slide with sample A or sample B on a 1000-mesh sandpaper. Then, the sample was slowly pushed forward 15 cm under the action of external force, and then the sample was rotated by 90°, and the above steps were repeated. This process was defined as one wear cycle. From Figure 7 As can be seen, after five wear cycles, the super-hydrophobic coating on the surface of sample A was damaged, while sample B containing the PDMS preformed layer still maintained integrity, and the super-hydrophobic coating on the surface was not damaged. The synergistic effect of the double-layer structure can improve the friction resistance.

Claims

1. A method for preparing a durable superhydrophobic carbon nanotube thin film composite material, characterized in that, The method comprises the following steps: Step 1: pretreat the carbon nanotube film substrate, fix the long strip-shaped carbon nanotube film on a stainless steel plate, and then put it into a plasma cleaning chamber for cleaning to remove surface impurities; Step 2: dissolve polydimethylsiloxane and a curing agent in n-hexane, perform ultrasonic treatment to form a prefabricated layer of polydimethylsiloxane; Step 3: disperse nano-silicon dioxide particles in n-hexane, perform ultrasonic treatment, then add octadecyltrichlorosilane, and perform stirring in a normal temperature water bath to prepare solution A; Step 4: weigh a proper amount of polydimethylsiloxane and a curing agent, dissolve them in solution A, perform ultrasonic treatment, and then perform magnetic stirring to prepare solution B; Step 5: coat the prefabricated layer of polydimethylsiloxane obtained in Step 2 on the pretreated carbon nanotube film substrate for pre-curing, then spray solution B obtained in Step 4 on the surface of the carbon nanotube film substrate, and put it into an oven for curing to obtain a durable super-hydrophobic carbon nanotube film composite material.

2. The method of claim 1, wherein the method is characterized by: The plasma cleaning power in Step 1 is 70 W, and the cleaning time is 120 s.

3. The method of claim 1, wherein the method is characterized by: The mass ratio of polydimethylsiloxane to the curing agent in Step 2 is 10:1, and the ultrasonic treatment time is 30 min.

4. The method of claim 1, wherein the method is characterized by: The size of the nano-silicon dioxide particles in Step 3 is 20±10 nm, the ultrasonic treatment time is 20 min, the mass ratio of nano-silicon dioxide to octadecyltrichlorosilane is 8:5, and the water bath stirring time is 2 h.

5. The method of claim 1, wherein the method is characterized by: The mass ratio of polydimethylsiloxane to the curing agent in Step 4 is 10:1, the ultrasonic treatment time is 30 min, and the magnetic stirring time is 2 h.

6. The method of claim 1, wherein the method is characterized by: The pre-curing temperature in Step 5 is 80℃, and the time is 20 min; the curing temperature is 100℃, and the time is 2 h.

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