CN111114040B

CN111114040B - Solvent steam driven type super-hydrophobic film and preparation method thereof

Info

Publication number: CN111114040B
Application number: CN201911411278.7A
Authority: CN
Inventors: 李红强; 苏晓竞; 曾幸荣; 赖学军; 陈中华
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2021-05-14
Anticipated expiration: 2039-12-31
Also published as: CN111114040A

Abstract

The invention discloses a solvent vapor driving type super-hydrophobic film and a preparation method thereof. The super-hydrophobic film is formed by hot pressing a PVDF layer, a cross-linked PVA layer, a semi-cured PDMS layer and an inorganic nano particle/PDMS coating from bottom to top; the cross-linked PVA layer is formed by coating a mixture of polyvinyl alcohol aqueous solution, glyoxal and hydrochloric acid on the surface of a PVDF film and performing cross-linking reaction at room temperature; the inorganic nano particle/PDMS coating is formed by sequentially carrying out vacuum filtration and solidification on an inorganic nano particle dispersion and a polydimethylsiloxane dispersion on a polyvinylidene fluoride porous filter membrane; the water contact angle of the film prepared by the invention reaches 168 degrees, and the film has excellent chemical stability. Meanwhile, the film can respond to various solvent vapors, realizes rapid and large-amplitude curling deformation, and has important application prospects in the aspects of water prevention, self cleaning, solvent detection, intelligent drivers and the like.

Description

Solvent steam driven type super-hydrophobic film and preparation method thereof

Technical Field

The invention relates to the field of super-hydrophobic films, in particular to a solvent steam driven super-hydrophobic film and a preparation method thereof.

Background

Inspired by animals and plants such as lotus leaves, rose petals, butterfly wings, water strider legs and the like in the nature, people find that the super-hydrophobic material exists, the contact angle of the static water drop on the surface of the super-hydrophobic material is more than 150 degrees, and the rolling angle is less than 10 degrees. In the last two decades, researchers have proposed methods such as a vapor deposition method, a layer-by-layer assembly method, a chemical etching method, an electrostatic spinning method and a spraying method to prepare a super-hydrophobic material, and gradually apply the super-hydrophobic material to the fields of self-cleaning, ice coating prevention, water surface resistance reduction, oil-water separation and the like. However, most of the prepared super-hydrophobic materials still have the defects of poor flexibility, temperature stability, solvent stability and the like.

With the rapid development of modern industry and artificial intelligence, the demand of people for functional super-hydrophobic materials becomes more urgent. The intelligent driving material is a novel functional material which can change shape under external stimulation of electricity, heat, light, a magnetic field, a solvent, humidity and the like, and has important research value and application prospect in the fields of soft bionic robots, sensors, artificial muscles and the like. Endowing intelligent drivable performance to the super-hydrophobic material not only can widen the application field of the super-hydrophobic material, but also can avoid inaccurate response of the driving behavior of the material in the environments of humidity, acid and alkali and the like. At present, researches related to the drivable super-hydrophobic material are rarely reported, and the reported driving material has no hydrophobicity and has the defects of slow response time, small bending amplitude and the like. Therefore, it is important to develop a functional drivable superhydrophobic material with excellent chemical stability, fast response speed and large deformation amplitude.

Disclosure of Invention

The invention provides a solvent vapor driving type super-hydrophobic film and a preparation method thereof, aiming at the defects of poor temperature stability, solvent intolerance, single function, no hydrophobicity of a driving material, low response speed, small deformation amplitude and the like of the existing super-hydrophobic material.

Firstly, dripping polyvinylidene fluoride (PVDF) solution on the surface of glass and drying at low temperature; secondly, coating a mixed solution of polyvinyl alcohol (PVA), glutaraldehyde, hydrochloric acid and water on the surface of the PVDF film, and crosslinking at room temperature to form a film; and finally, coating Polydimethylsiloxane (PDMS) on the surface of the cross-linked PVA in a scraping way, and transferring the inorganic nano particle/PDMS composite coating on the filter membrane to the membrane after semi-solidification to obtain the solvent steam driven super-hydrophobic membrane. The film prepared by the invention has excellent hydrophobicity and chemical stability, can respond to various solvent vapors, realizes rapid and large-amplitude curling deformation, and has important application prospects in the aspects of waterproof self-cleaning, solvent detection, intelligent drivers and the like.

The purpose of the invention is realized by the following technical scheme:

a solvent steam driven type super-hydrophobic film is formed by a PVDF layer, a cross-linked PVA layer, a semi-cured PDMS layer and an inorganic nano particle/PDMS coating in a hot pressing mode from bottom to top; the cross-linked PVA layer is formed by coating a mixture of polyvinyl alcohol aqueous solution, glyoxal and hydrochloric acid on the surface of a PVDF film and performing cross-linking reaction at room temperature;

the inorganic nano particle/PDMS coating is formed by sequentially carrying out vacuum filtration and curing on an inorganic nano particle dispersion and a polydimethylsiloxane dispersion on a polyvinylidene fluoride porous filter membrane;

solvent vapor driven super-hydrophobic filmThe water contact angle is 155-168 DEG at room temperature; the film is placed in an environment with the temperature of-5 to 150 ℃ or treated by solvent vapor for 72 hours, and the surface contact angle of the film is kept above 150 degrees; the film is bent to the super-hydrophobic surface in the solvent steam for 5-60s to realize the curvature of 0.5-0.8mm^-1Large amplitude deformation.

To further achieve the object of the present invention, preferably, the solvent vapor driving of the film is caused by a significant difference in swelling of the PVDF film and the crosslinked PVA layer in the solvent vapor; the solvent vapor includes one or two of acetone vapor, tetrahydrofuran vapor, N-dimethylformamide vapor, pyridine vapor, dichloromethane vapor and ethyl acetate vapor.

The preparation method of the solvent steam driven type super-hydrophobic film comprises the following steps:

1) adding polyvinylidene fluoride (PVDF) powder into an organic solvent A, uniformly stirring, dripping the solution on glass treated by oxygen plasma, and drying; adding polyvinyl alcohol (PVA) particles into water, stirring, adding glyoxal and hydrochloric acid, uniformly mixing, coating on the surface of a PVDF film, and carrying out crosslinking reaction for 2-4h at room temperature to form a crosslinked PVA layer;

2) adding inorganic nanoparticles into an organic solvent B, performing ultrasonic dispersion to form a dispersion solution 1, adding Polydimethylsiloxane (PDMS) into an organic solvent C, and stirring at room temperature to form a dispersion solution 2; sequentially carrying out vacuum filtration on the dispersion liquid 1 and the dispersion liquid 2 on a polyvinylidene fluoride porous filter membrane, taking out the filter membrane, and curing to form an inorganic nano particle/PDMS coating;

3) coating Polydimethylsiloxane (PDMS) on the cross-linked PVA layer in a scraping way, and heating at the temperature of 60-80 ℃ to form a semi-cured PDMS layer; pressing the inorganic nano particle/PDMS coating on the filter membrane onto the semi-solidified PDMS layer, heating at 80-100 deg.C, removing the filter membrane, and taking off the membrane from the glass to obtain the solvent vapor driven super-hydrophobic membrane.

Preferably, the mass volume ratio of the polyvinylidene fluoride to the organic solvent A is 0.05-0.08 g/mL; the organic solvent A is any one or a mixture of two of N, N-dimethylformamide and N-methylpyrrolidone.

Preferably, the mass ratio of the polyvinyl alcohol to the water in the step 1) is 3:50-3:25g/mL, the mass ratio of the glyoxal to the polyvinyl alcohol is 3:100-3:50, and the mass ratio of the hydrochloric acid to the polyvinyl alcohol is 1:100-1: 50; the step 1) of uniformly stirring is to stir for 1 to 4 hours at a temperature of between 50 and 100 ℃; the glyoxal and the hydrochloric acid are added after stirring, and the stirring is carried out for 3 to 6 hours at the temperature of between 60 and 90 ℃; the drying in step 1) is carried out at 30-50 ℃ for 12 h.

Preferably, the inorganic nanoparticles in step 2) are any one of silica, ferroferric oxide, silver nanowires, silver particles, carbon nanotubes and carbon black; the ultrasonic dispersion time is 0.5-2 h; stirring the mixture at room temperature to form the dispersion liquid 2 for 5-15 min; the pore diameter of the polyvinylidene fluoride porous filter membrane is 0.22 or 0.45 mu m; the curing is carried out at 80-100 ℃ for 0.5-2 h.

Preferably, the particle size of the silicon dioxide, the ferroferric oxide, the silver particles and the carbon black is 30-300nm, and the diameter of the silver nanowires and the carbon nanotubes is 20-50 nm.

Preferably, the organic solvent B is any one of toluene, ethanol, acetone and N, N-dimethylformamide; the organic solvent C is any one of toluene, tetrahydrofuran and hexane; the polydimethylsiloxane is any one of Sylgard 184 and Sylgard 186 in Dow Corning USA.

Preferably, the mass-volume ratio of the inorganic nanoparticles to the organic solvent B is 0.2-1 mg/mL; the mass-volume ratio of the polydimethylsiloxane to the organic solvent C is 0.01-0.05 mg/mL; step 3); the thickness of the PDMS blade-coated on the cross-linked PVA layer is 10-25 μm.

Preferably, the heating time at 60-80 ℃ in the step 3) is 15-40 min; heating at 80-100 deg.C for 1-2 h; polydimethylsiloxane blade coating the polydimethylsiloxane coating was controlled to a thickness of 10-25 μm on the crosslinked PVA layer.

Compared with the prior art, the invention has the following advantages:

(1) the film prepared by the invention has both super-hydrophobicity and solvent vapor driving property, and belongs to a multifunctional composite material;

(2) the solvent vapor driving type super-hydrophobic film prepared by the invention has excellent flexibility and chemical stability, and can keep super-hydrophobicity after being treated by low temperature, high temperature and solvent vapor.

(3) The solvent vapor driven super-hydrophobic film prepared by the invention responds to various solvent vapors, realizes rapid and large-amplitude bending deformation, and has important application value in solvent detection and intelligent drivers.

Drawings

FIG. 1 is a deformation process of the solvent vapor-driven superhydrophobic film prepared in example 1 after being placed in acetone vapor and removed therefrom.

Fig. 2 is a graph showing the change of curvature with time after the solvent vapor-driven superhydrophobic film prepared in example 1 was placed in acetone vapor and removed therefrom.

Detailed description of the invention

The present invention will be further described with reference to the following examples for better understanding of the present invention, but the embodiments of the present invention are not limited thereto.

The film contact angle was measured using a DSA100 tester from KRUSS, Germany, and 5 points were taken for each sample to calculate an average value.

Example 1

A method for preparing a solvent vapor driving type super-hydrophobic film;

firstly, PVDF powder is added into N-methyl pyrrolidone according to the mass-to-volume ratio of 0.0625g/mL, stirred for 3 hours at the temperature of 60 ℃, then the solution is dripped on glass treated by oxygen plasma (300W, 1min), and dried for 12 hours at the temperature of 40 ℃; then, adding PVA particles into water according to the mass ratio of 7:93, stirring for 4 hours at the temperature of 80 ℃, sequentially adding glyoxal and hydrochloric acid (the mass ratio of the glyoxal to the PVA particles is 1: 20; the mass ratio of the hydrochloric acid to the PVA particles is 1:50), uniformly mixing, coating on the surface of a PVDF film, and carrying out crosslinking reaction for 2 hours at room temperature to form a crosslinked PVA layer;

secondly, adding 15mg of carbon nano tube (CNT, Aladdin reagent Co., Ltd.) with the diameter of 20-40nm into 50mL of N, N-dimethylformamide, carrying out ultrasonic dispersion for 1h to form a dispersion solution 1, adding 0.05g of PDMS (Sylgard 186) into 5mL of toluene, stirring for 10min at room temperature to form a dispersion solution 2, sequentially carrying out vacuum filtration on the dispersion solution 1 and the dispersion solution 2 on a polyvinylidene fluoride porous filter membrane (0.45 mu m), taking out the filter membrane, and curing for 0.5h at 100 ℃ to form a CNT/PDMS coating;

and finally, coating PDMS (Sylgard 186) on a cross-linked PVA layer (the thickness of the PDMS is about 15 mu m) in a scraping way, heating at 80 ℃ for 15min to form a semi-cured PDMS layer, pressing the CNT/PDMS coating on the filter membrane onto the semi-cured PDMS layer with force, heating at 100 ℃ for 1h, uncovering the filter membrane, and taking the film off the glass to prepare the solvent steam driven type super-hydrophobic film.

Table 1 lists the initial contact angles and the contact angles after the low-temperature, high-temperature, solvent vapor treatment of the solvent vapor driving type superhydrophobic film prepared in this example. Due to the micro-nano rough structure of the CNT structure and the modification of the PDMS with low surface energy, the initial contact angle of the surface of the film is 162 degrees, and the film has excellent super-hydrophobicity.

In order to evaluate the chemical stability of the solvent vapor driving type superhydrophobic film prepared in this example, it was left in an environment of-5 deg.c, 80 deg.c, and 150 deg.c for 72 hours, respectively, and the surface contact angle was tested. Meanwhile, the prepared film was placed in a closed solvent vapor (including acetone, dichloromethane, and tetrahydrofuran) for 72h, and the surface contact angle was tested. As can be seen from Table 1, the contact angle of the film after being treated in acetone, dichloromethane and tetrahydrofuran vapor at-5 deg.C, 80 deg.C and 150 deg.C for 72h is still over 155 deg.C, and the film has excellent temperature resistance and solvent resistance.

To evaluate the driving behavior of the solvent vapor-driven type superhydrophobic film prepared in this example, 10mL of solvent was added to a100 mL beaker, the film was placed 1cm above the acetone solvent, and the deformation process of the film in the vapor formed by the volatilization of the solvent was recorded with a camera, and the result was shown in fig. 2. As can be seen from fig. 2, the film was greatly curled toward the superhydrophobic surface within 5 seconds in acetone vapor, and the film was returned to the original state after being taken out from the vapor. The bending amplitude of the film is evaluated by adopting curvature (kappa), and the curvature is calculated by the formula

Where θ is the film bend angle and L is the film length, the resulting curve of curvature over time is shown in FIG. 2. As can be seen from fig. 2, the curvature of the film shows a tendency to increase gradually as the film is left in the acetone vapor for a longer period of time. The reason is that the PVDF layer in the film can rapidly absorb acetone molecules to swell, and the cross-linked PVA layer cannot swell or dissolve in any organic solvent; the obvious difference of the swelling properties of PVDF and cross-linked PVA in a solvent causes the film to curl towards a super-hydrophobic surface rapidly and greatly; when the film was removed from the acetone vapor, the acetone molecules quickly detached from the PVDF layer, causing the film curvature to gradually decrease and recover. Meanwhile, table 2 lists the driving solvent and the curvature in the solvent vapor for 60s of the solvent vapor driving-type superhydrophobic film prepared in this example. As can be seen from Table 2, the film was driven by acetone vapor, and was left in acetone vapor for 60 seconds with a curvature of 0.8mm^-1A large amount of curling deformation occurs.

The solvent vapor driving type super-hydrophobic film prepared by the invention has excellent chemical stability, has solvent driving performance, can realize rapid and large-amplitude bending deformation, and has important application value in self-cleaning, solvent detection and intelligent drivers. Most of the super-hydrophobic materials reported at present only have a single hydrophobic function, and are difficult to meet the application requirements in the emerging fields of wearable electronic technology, artificial intelligence and the like. Meanwhile, the service life of the material is still to be improved under the influence of the chemical stability of the super-hydrophobic surface. The super-hydrophobic film prepared by the invention adopts the PDMS matrix, keeps super-hydrophobic after low-temperature, high-temperature and solvent steam treatment, has excellent chemical stability, and effectively prolongs the service life of the film in a severe environment. In addition, the super-hydrophobic film prepared by the invention effectively introduces intelligent drivability, and the significant difference of the swelling properties of the PVDF layer and the cross-linked PVA layer in the film in solvent steam causes the film to rapidly realize large-scale curling deformation, thereby greatly widening the application of the film in the fields of solvent detection and intelligent drivers. Meanwhile, it is noted that due to the super-hydrophobic temperature resistance and solvent resistance of the film, the prepared film can maintain normal solvent vapor driving performance even in a humid environment, which greatly improves the deformation stability of the film and ensures the long-term use of the film in a severe environment.

Example 2

A method for preparing a solvent vapor driving type super-hydrophobic film;

firstly, adding PVDF powder into N, N-dimethylformamide according to the mass-to-volume ratio of 0.05g/mL, stirring for 4 hours at 50 ℃, dripping the solution on glass treated by oxygen plasma, and drying for 12 hours at 50 ℃; then, adding PVA particles into water according to the mass ratio of 3:50, stirring for 6h at 60 ℃, sequentially adding glyoxal and hydrochloric acid (the mass ratio of the glyoxal to the PVA particles is 3: 100; the mass ratio of the hydrochloric acid to the PVA particles is 1:100), uniformly mixing, coating on the surface of a PVDF film, and carrying out crosslinking reaction for 3h at room temperature to form a crosslinked PVA layer;

next, 50mg of Silica (SiO) having a diameter of 300nm was added₂Avadin reagent limited) was added to 50mL of ethanol, ultrasonic dispersion was carried out for 1.5 hours to form dispersion 1, 0.25g of PDMS (Sylgard 184) was added to 5mL of tetrahydrofuran, and stirred at room temperature for 15 minutes to form dispersion 2, and then the dispersion 1 and the dispersion 2 were subjected to vacuum filtration in this order on a polyvinylidene fluoride porous filter membrane (0.22 μm), and the filter membrane was taken out and cured at 80 ℃ for 2 hours to form SiO₂A PDMS coating;

finally, PDMS was drawn on a crosslinked PVA layer (PDMS draw thickness about 10 μm), heated at 60 ℃ for 40min to form a semi-cured PDMS layer, and SiO on the filter membrane was applied₂Pressing the PDMS coating on the semi-cured PDMS layer with force, heating at 80 ℃ for 2h, removing the filter membrane, and taking off the film from the glass to obtain the solvent vapor driven super-hydrophobic film.

Table 1 lists the initial contact angles and the contact angles after the low-temperature, high-temperature, solvent vapor treatment of the solvent vapor driving type superhydrophobic film prepared in this example. As can be seen from Table 1, the initial contact angle of the film surface is 168 degrees, and after the film surface is treated in acetone, dichloromethane and tetrahydrofuran steam at-5, 80 and 150 ℃ for 72 hours, the contact angle is still kept above 155 degrees, and the film surface has excellent hydrophobicity and chemical stability. Table 2 shows the solvent vapor-driven type superhydrophobic film prepared in this exampleKinetic solvent and curvature in solvent vapor for 60 s. As can be seen from Table 2, the film was driven by pyridine vapor, which was left standing for 60 seconds with a curvature of 0.65mm^-1The method has the advantages of high response speed, large curling amplitude and the like.

Example 3

A method for preparing a solvent vapor driving type super-hydrophobic film;

firstly, PVDF powder is added into a mixed solvent (volume ratio is 1:1) of N, N-dimethylformamide and N-methylpyrrolidone according to the mass-volume ratio of 0.08g/mL, the mixture is stirred for 1h at 100 ℃, then the solution is dripped on glass treated by oxygen plasma, and the glass is dried for 12h at 30 ℃; then, adding PVA particles into water according to the mass ratio of 3:25, stirring for 3 hours at 90 ℃, sequentially adding glyoxal and hydrochloric acid (the mass ratio of the glyoxal to the PVA particles is 3: 50; the mass ratio of the hydrochloric acid to the PVA particles is 1:50), uniformly mixing, coating on the surface of a PVDF film, and carrying out crosslinking reaction for 4 hours at room temperature to form a crosslinked PVA layer;

next, 10mg of ferroferric oxide (Fe) having a diameter of 30nm was added₃O₄Avadin reagent limited) was added to 50mL of toluene, ultrasonic dispersion was performed for 0.5h to form dispersion 1, 0.1g of PDMS (Sylgard 184) was added to 5mL of hexane, stirring was performed at room temperature for 20min to form dispersion 2, vacuum filtration was sequentially performed on the dispersion 1 and the dispersion 2 on a polyvinylidene fluoride porous filter membrane (0.22 μm), the filter membrane was taken out, and curing was performed at 100 ℃ for 1h to form Fe₃O₄A PDMS coating;

finally, PDMS was drawn on a crosslinked PVA layer (PDMS draw thickness about 20 μm), heated at 70 ℃ for 30min to form a semi-cured PDMS layer, Fe on the filter membrane₃O₄Pressing PDMS coating onto semi-cured PDMS layer, heating at 90 deg.C for 1.5h, removing the filter membrane, and taking off the film from glass to obtain the final product.

Table 1 lists the initial contact angles and the contact angles after the low-temperature, high-temperature, solvent vapor treatment of the solvent vapor driving type superhydrophobic film prepared in this example. As can be seen from Table 1, the initial surface contact angle of the film was 159 °, at-5, 80 and 150 ℃ and acetone, dichloromethane, tetrahydrofuran vaporsAfter the medium treatment for 72h, the contact angle is still kept above 155 degrees, and the water repellency and the chemical stability are excellent. Table 2 lists the driving solvent and the curvature in the solvent vapor for 60s for the solvent vapor driving type superhydrophobic film prepared in this example. As can be seen from Table 2, the film was driven by tetrahydrofuran vapor with a curvature of 0.72mm for 60s^-1The method has the advantages of high response speed, large curling amplitude and the like.

Example 4

A method for preparing a solvent vapor driving type super-hydrophobic film;

firstly, adding PVDF powder into N-methyl pyrrolidone according to the mass-to-volume ratio of 0.07g/mL, stirring for 2h at 70 ℃, dripping the solution on glass treated by oxygen plasma, and drying for 12h at 40 ℃; then, adding PVA particles into water according to the mass ratio of 2:25, stirring for 3 hours at 70 ℃, sequentially adding glyoxal and hydrochloric acid (the mass ratio of the glyoxal to the PVA particles is 3: 70; the mass ratio of the hydrochloric acid to the PVA particles is 1:75), uniformly mixing, coating on the surface of a PVDF film, and carrying out crosslinking reaction for 2 hours at room temperature to form a crosslinked PVA layer;

secondly, adding 25mg of carbon black (CB, Allantin reagent Co., Ltd.) with the diameter of 50nm into 50mL of ethanol, performing ultrasonic dispersion for 2h to form a dispersion solution 1, adding 0.15g of PDMS (Sylgard 186) into 5mL of toluene, stirring at room temperature for 25min to form a dispersion solution 2, performing vacuum filtration on the dispersion solution 1 and the dispersion solution 2 on a polyvinylidene fluoride porous filter membrane (0.45 mu m) in sequence, taking out the filter membrane, and curing at 90 ℃ for 1.5h to form a CB/PDMS coating;

and finally, coating PDMS on a cross-linked PVA layer (the thickness of the PDMS is about 25 μm), heating at 80 ℃ for 20min to form a semi-cured PDMS layer, pressing the CB/PDMS coating on the filter membrane onto the semi-cured PDMS layer with force, heating at 80 ℃ for 2h, uncovering the filter membrane, and taking the film off the glass to obtain the solvent steam driven super-hydrophobic film.

Table 1 lists the initial contact angles and the contact angles after the low-temperature, high-temperature, solvent vapor treatment of the solvent vapor driving type superhydrophobic film prepared in this example. As can be seen from Table 1, the initial surface contact angle of the film was 168 deg., at-5, 80 and 150 deg.C andafter the membrane is treated in acetone, dichloromethane and tetrahydrofuran vapor for 72 hours, the contact angle is still kept above 155 degrees, and the membrane has excellent hydrophobicity and chemical stability. Table 2 lists the curvature of the driving solvent in the solvent vapor for the solvent vapor driving type superhydrophobic film prepared in this example for 60 s. As can be seen from Table 2, the film was driven by N, N-dimethylformamide vapor, which was allowed to stand for 60 seconds and reached a curvature of 0.58mm^-1The method has the advantages of high response speed, large curling amplitude and the like.

Table 1 shows initial contact angles and contact angles after low-temperature, high-temperature, solvent vapor treatment of the solvent vapor driven type superhydrophobic thin films prepared in examples of the present invention.

TABLE 1

Table 2 shows the driving solvent and the curvature in the solvent vapor for the solvent vapor driving type superhydrophobic film prepared in the example of the present invention for 60 s.

TABLE 2

The embodiments of the present invention are not limited to the embodiments described above, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and they are included in the scope of the present invention.

Claims

1. A solvent steam driven type super-hydrophobic film is characterized by being formed by hot pressing of a PVDF layer, a cross-linked PVA layer, a semi-cured PDMS layer and an inorganic nano particle/PDMS coating from bottom to top; the cross-linked PVA layer is formed by coating a mixture of polyvinyl alcohol aqueous solution, glyoxal and hydrochloric acid on the surface of a PVDF film and performing cross-linking reaction at room temperature;

the water contact angle of the solvent vapor driven super-hydrophobic film at room temperature is 155-168 degrees; the film is placed in an environment with the temperature of-5 to 150 ℃ or treated by solvent vapor for 72 hours, and the surface contact angle of the film is kept above 150 degrees; the film is bent to the super-hydrophobic surface in the solvent steam for 5-60s to realize the curvature of 0.5-0.8mm^-1Large amplitude deformation.

2. The solvent vapor driven superhydrophobic film of claim 1, wherein the solvent vapor driving of the film is caused by a significant difference in swelling of the PVDF film and the crosslinked PVA layer in solvent vapor; the solvent vapor includes one or two of acetone vapor, tetrahydrofuran vapor, N-dimethylformamide vapor, pyridine vapor, dichloromethane vapor and ethyl acetate vapor.

3. The method for preparing the solvent vapor driving type superhydrophobic film according to claim 1 or 2, characterized by comprising the steps of:

1) adding polyvinylidene fluoride powder into an organic solvent A, stirring uniformly, dripping the solution on glass treated by oxygen plasma, and drying; adding polyvinyl alcohol particles into water, stirring, adding glyoxal and hydrochloric acid, uniformly mixing, coating on the surface of a PVDF film, and carrying out crosslinking reaction for 2-4h at room temperature to form a crosslinked PVA layer;

2) adding inorganic nanoparticles into an organic solvent B, performing ultrasonic dispersion to form a dispersion solution 1, adding polydimethylsiloxane into an organic solvent C, and stirring at room temperature to form a dispersion solution 2; sequentially carrying out vacuum filtration on the dispersion liquid 1 and the dispersion liquid 2 on a polyvinylidene fluoride porous filter membrane, taking out the filter membrane, and curing to form an inorganic nano particle/PDMS coating;

3) coating polydimethylsiloxane on the cross-linked PVA layer in a blade mode, and heating at the temperature of 60-80 ℃ to form a semi-cured PDMS layer; pressing the inorganic nano particle/PDMS coating on the filter membrane onto the semi-solidified PDMS layer, heating at 80-100 deg.C, removing the filter membrane, and taking off the membrane from the glass to obtain the solvent vapor driven super-hydrophobic membrane.

4. The method of preparing the solvent vapor driving type superhydrophobic film according to claim 3, characterized in that: the mass volume ratio of the polyvinylidene fluoride to the organic solvent A is 0.05-0.08 g/mL; the organic solvent A is any one or a mixture of two of N, N-dimethylformamide and N-methylpyrrolidone.

5. The method of preparing the solvent vapor driving type superhydrophobic film according to claim 3, characterized in that: the mass ratio of the polyvinyl alcohol to the water in the step 1) is 3:50-3:25g/mL, the mass ratio of the glyoxal to the polyvinyl alcohol is 3:100-3:50, and the mass ratio of the hydrochloric acid to the polyvinyl alcohol is 1:100-1: 50; the step 1) of uniformly stirring is to stir for 1 to 4 hours at a temperature of between 50 and 100 ℃; the glyoxal and the hydrochloric acid are added after stirring, and the stirring is carried out for 3 to 6 hours at the temperature of between 60 and 90 ℃; the drying in step 1) is carried out at 30-50 ℃ for 12 h.

6. The method of preparing the solvent vapor driving type superhydrophobic film according to claim 3, characterized in that: the inorganic nano particles in the step 2) are any one of silicon dioxide, ferroferric oxide, silver nanowires, silver particles, carbon nano tubes and carbon black; the ultrasonic dispersion time is 0.5-2 h; stirring the mixture at room temperature to form the dispersion liquid 2 for 5-15 min; the pore diameter of the polyvinylidene fluoride porous filter membrane is 0.22 or 0.45 mu m; the curing is carried out at 80-100 ℃ for 0.5-2 h.

7. The method of preparing the solvent vapor driving type superhydrophobic film according to claim 6, wherein: the particle diameters of the silicon dioxide, the ferroferric oxide, the silver particles and the carbon black are 30-300nm, and the diameters of the silver nanowires and the carbon nanotubes are 20-50 nm.

8. The method of preparing the solvent vapor driving type superhydrophobic film according to claim 3, characterized in that: the organic solvent B is any one of toluene, ethanol, acetone and N, N-dimethylformamide; the organic solvent C is any one of toluene, tetrahydrofuran and hexane; the polydimethylsiloxane is any one of Sylgard 184 and Sylgard 186.

9. The method of preparing the solvent vapor driving type superhydrophobic film according to claim 3, characterized in that: the mass volume ratio of the inorganic nanoparticles to the organic solvent B is 0.2-1 mg/mL; the mass-volume ratio of the polydimethylsiloxane to the organic solvent C is 0.01-0.05 mg/mL; step 3); the thickness of the PDMS blade-coated on the cross-linked PVA layer is 10-25 μm.

10. The method of preparing the solvent vapor driving type superhydrophobic film according to claim 3, characterized in that: the heating time at 60-80 ℃ in the step 3) is 15-40 min; heating at 80-100 deg.C for 1-2 h; polydimethylsiloxane blade coating the polydimethylsiloxane coating was controlled to a thickness of 10-25 μm on the crosslinked PVA layer.