CN111116056B

CN111116056B - A kind of electrothermally discolored superhydrophobic film and preparation method thereof

Info

Publication number: CN111116056B
Application number: CN201911408755.4A
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: 2021-07-20
Anticipated expiration: 2039-12-31
Also published as: CN111116056A

Abstract

The invention discloses a super-hydrophobic film with electro-heating discoloration and a preparation method thereof. In the preparation method, the graphene oxide solution is firstly drop-coated on the glass surface and dried at low temperature, and then hydrogen iodide/acetic acid is used as a reducing agent to prepare a reduced graphene oxide film; secondly, the hydrophobic polymer solution is coated on the reduced oxidation The front side of the graphene film forms a base layer; finally, the hydrophobic polymer, the dispersion of the high-temperature color-changing microcapsules in an organic solvent, the hydrophobic polymer, and the dispersion of the low-temperature color-changing microcapsules in the organic solvent are sprayed onto the reduced graphite oxide in turn. A multi-level discoloration layer is formed on the reverse side of the alkene film to prepare a superhydrophobic film with electrothermal color change. The film prepared by the invention has a water contact angle of 160°, has excellent electrothermal effect, can realize three-color transformation on the surface, and has important application prospects in waterproof self-cleaning and environmental temperature indication.

Description

Super-hydrophobic thin film with electrochromic effect by electric heating and preparation method thereof

Technical Field

The invention relates to a super-hydrophobic film, in particular to an electrochromic super-hydrophobic film and a preparation method thereof.

Background

In recent years, with the vigorous development of composite materials, diversification of material functions has been emphasized. The super-hydrophobic material is a material with a surface static water drop contact angle larger than 150 degrees and a rolling angle smaller than 10 degrees, and has wide application prospects in the fields of self-cleaning, ice coating prevention, pollution prevention, drag reduction, oil-water separation and the like. However, the existing super-hydrophobic material has single function and is difficult to meet the use requirements of a plurality of emerging fields.

The intelligent material is a material which can timely and accurately sense the external environmental conditions and changes and make judgment, processing and reaction. The intelligent color-changing material can perform reversible color transformation under the stimulation of external conditions such as heat, light wave irradiation, voltage and the like, and has important prospects in the fields of anti-counterfeiting marks, temperature indication, daily decoration and the like, so that the intelligent color-changing material is concerned by many scholars at home and abroad. Endowing the intelligent temperature-sensitive color-changing performance to the super-hydrophobic material not only can widen the application field of the super-hydrophobic material, but also can avoid the color-changing performance of the material from being damaged when the material is used in the environments of humidity, acid and alkali and the like for a long time. However, few studies related to the color-changeable super-hydrophobic material are reported at present. Chinese invention patents CN102561043A and CN104249534A disclose a color-changing super-hydrophobic fabric and a preparation method thereof, but the method is only applicable to fabric substrates. In addition, the super-hydrophobic coating with thermochromic performance is prepared by performing hydrophobic modification on temperature-sensitive powder by Liangheiming and the like, mixing the temperature-sensitive powder with a styrene-butadiene-styrene block copolymer and spraying the mixture on a substrate, but the coating only responds to one temperature and only realizes the conversion of two colors (Liangheiming, Van Jun, Wang Ciyuan and the like, stable preparation and characterization of the temperature-sensitive photochromic super-hydrophobic coating, contemporary chemical engineering, 2019, 48(8), 1660-. The Chinese patent application 2019106750150 discloses an electrochromic/deformable film and a preparation method thereof, the electrochromic/deformable film comprises a substrate layer, an electrochromic layer, a bottom color layer, at least two color-changing layers and a packaging layer covering and wrapping the above layers, which are arranged from bottom to top, wherein the upper surface of the packaging layer is provided with a deformable layer capable of realizing surface pattern change; wherein the color changing layer is composed of reversible thermochromic microcapsules, and the color changing temperature is 35-80 ℃; the deformation layer is formed by solidifying thermosetting epoxy resin with shape memory property and endowing the thermosetting epoxy resin with patterns, and the deformation temperature is 40-120 ℃. The preparation method of the electrochromic/deformable film comprises the following steps: and respectively assembling the multilayer structures of the electric heating layer, the bottom color layer, the color changing layer and the packaging material on the basal layer from bottom to top by a suction filtration method, and constructing a deformation layer on the surface of the packaging material. The temperature of the electric heating layer is controlled by a circuit, so that the film can generate multiple reversible color changes and synchronous change of color change and deformation. However, the preparation method of the film is complex and expensive, and the hydrophilicity of the epoxy resin on the surface of the film can adsorb impurities such as dust and the like, so that the color display is influenced. The prior art also has difficulty in achieving a combination of multiple color changes and superhydrophobicity.

Disclosure of Invention

Aiming at the defects that the existing super-hydrophobic material is single in function and the intelligent color-changing super-hydrophobic material does not have universality and can not realize various color changes, the invention provides the functional super-hydrophobic film with the electrochromism and the preparation method thereof, the obtained film has the advantages of excellent hydrophobicity, electrothermal effect and the like, and the film can quickly realize the reversible transformation of three colors under the condition of low voltage application and removal.

According to the invention, firstly, hydrogen iodide/acetic acid is used as a reducing agent to prepare a reduced graphene oxide (rGO) film, then a solution of a hydrophobic polymer is coated on the front surface of the rGO film, and the hydrophobic polymer, a dispersion liquid of high-temperature color-changing microcapsules in an organic solvent, the hydrophobic polymer and a dispersion liquid of low-temperature color-changing microcapsules in the organic solvent are sequentially sprayed on the back surface of the rGO film to prepare the electrochromism super-hydrophobic film. The film prepared by the invention has super-hydrophobicity, the surface can realize the conversion of three colors under the electrothermal effect, and the film has important application prospect in the aspects of water resistance, self-cleaning, environmental temperature indication and the like.

The invention provides an electrochromic super-hydrophobic film and a preparation method thereof by combining an rGO (red graphene oxide) electric heating layer with a substrate layer and an electrochromic super-hydrophobic layer. Wherein, rGO is low in price, large-area production is easy to realize by a spraying method, and the film has three color changes. The super-hydrophobicity of the surface of the film can endow the film with excellent self-cleaning performance, so that impurities on the surface of the film can be easily removed under water flushing, the bright color of the film is further ensured, and the super-hydrophobicity of the film can prevent the color-changing performance of the film from being damaged when the film is used in environments such as humidity, acid and alkali for a long time. Meanwhile, the multiple color-changing property of the super-hydrophobic film can endow the film with beautiful appearance, can make simple judgment on the temperature range of the current environment, and has important application value in the fields of reaction devices, warehouse supervision and the like.

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

an electrically heating color-changing super-hydrophobic film is a composite film and comprises a low-temperature color-changing layer, a high-temperature color-changing layer, an rGO electrically heating layer and a substrate layer from top to bottom;

the rGO electric heating layer is prepared by the following method: dispersing graphene oxide in water, uniformly performing ultrasonic treatment, dripping the graphene oxide on glass treated by oxygen plasma, and drying to obtain a GO film; adding hydrogen iodide into acetic acid, mixing, adding into GO film, and reducing at 50-100 deg.C; washing and drying to obtain a reduced graphene oxide (rGO) film, and bonding thin copper sheets serving as electrodes to two sides of the front surface of the reduced graphene oxide (rGO) film through conductive silver paste to prepare an rGO electric heating layer;

the low-temperature discoloring layer and the high-temperature discoloring layer are prepared by the following steps: adding a hydrophobic polymer into the organic solvent B, stirring, and adding a high-temperature color-changing microcapsule to prepare a dispersion liquid 1; dispersing hydrophobic polymer in the solution of organic solvent B, and adding low-temperature color-changing microcapsules to prepare dispersion liquid 2; and spraying the dispersion liquid 1 and the dispersion liquid 2 to the reverse side of a reduced graphene oxide (rGO) film in sequence to form a low-temperature color changing layer and a high-temperature color changing layer.

To further achieve the object of the present invention, preferably, the water contact angle of the electrochromic super-hydrophobic film at room temperature is 150-160 °; applying a voltage of less than 10V to the film, and raising the surface temperature of the film to 30-100 ℃ within 40 s; the film can realize the conversion of three colors when being heated and can be reversibly restored to the original color when being cooled.

The preparation method of the electrochromism super-hydrophobic film comprises the following steps:

1) dispersing 0.1-0.4 parts of graphene oxide in 100 parts of water, uniformly performing ultrasonic treatment, dripping the mixture on glass treated by oxygen plasma, and drying to obtain a GO film; adding 2-5 parts of hydrogen iodide into 10 parts of acetic acid, uniformly mixing, then putting the mixture into a GO film, and reducing at 50-100 ℃; washing and drying to obtain a reduced graphene oxide film (rGO film), and bonding thin copper sheets serving as electrodes on two sides of the front surface of the reduced graphene oxide film through conductive silver paste to obtain an rGO electric heating layer;

2) adding a hydrophobic polymer into an organic solvent A, uniformly stirring, dripping the obtained solution on the front surface of a reduced graphene oxide film (rGO film), and drying at room temperature to obtain a substrate layer; then adding the hydrophobic polymer into the organic solvent B, uniformly stirring, adding the high-temperature color-changing microcapsule, and performing ultrasonic dispersion to prepare a dispersion solution 1; dispersing a hydrophobic polymer in a solution of an organic solvent B, adding a low-temperature color-changing microcapsule, and performing ultrasonic dispersion to prepare a dispersion liquid 2; sequentially spraying the dispersion liquid 1 and the dispersion liquid 2 on the reverse side of a reduced graphene oxide film (rGO film) to form a multi-stage color-changing layer, wherein the spraying amount depends on the spraying condition, and drying at room temperature to obtain the super-hydrophobic film with the color changed by electric heating;

the hydrophobic polymer is any one of polyvinylidene fluoride-hexafluoropropylene copolymer, hydrogenated styrene-butadiene-styrene block copolymer and styrene-butadiene-styrene block copolymer.

Preferably, the organic solvent A is any one of N, N-dimethylformamide, N-methylpyrrolidone and dimethylacetamide; the organic solvent B is any one of acetone, toluene and tetrahydrofuran.

Preferably, the color change temperature of the low-temperature color-changing microcapsule is 31-65 ℃, and the color is changed into any one of color and colorless; the color change temperature of the high-temperature color change microcapsule is 45-80 ℃, and the color is changed into any one of color and color; the grain diameter of the color-changing microcapsule is 0.5-5 μm.

Preferably, the mass ratio of the hydrophobic polymer to the organic solvent A is 3:20-3:10, the mass ratio of the hydrophobic polymer to the organic solvent B is 1:25-7:100, the mass ratio of the low-temperature color-changing microcapsule to the hydrophobic polymer is 3:20-3:10, and the mass ratio of the high-temperature color-changing microcapsule to the hydrophobic polymer is 1:20-1: 10.

Preferably, the spraying working pressure is 0.2-0.4MPa, and the spraying distance between a spray gun and the reduced graphene oxide film (rGO film) is 10-20 cm; the spraying amount and the flow rate of the spraying dispersion liquid 1 are respectively 0.3-0.5 mL-cm^-2And 0.3-0.5mL · s^-1The spraying amount and the flow rate of the spraying dispersion liquid 2 are respectively 0.1-0.2 mL-cm^-2And 0.15-0.3mL · s^-1。

Preferably, in the step 1), the drying temperature of the GO film obtained after drying is 30-50 ℃, and the time is 12 hours; the reduction time at 50-100 ℃ is 2-30 min; the washing is repeated by water and methanol.

Preferably, in the step 2), in the preparation of the substrate layer, the stirring is performed for 3 to 8 hours at a temperature of between 50 and 100 ℃; in the preparation of the dispersion liquid 1, the uniform stirring is carried out for 3 to 5 hours at the temperature of between 30 and 60 ℃; the drying time at room temperature is 3-6 h.

Preferably, in the step 2), the ultrasonic dispersion time is 5-10min in the preparation of the dispersion liquid 1 and the dispersing agent 2.

Compared with the prior art, the electrochromism super-hydrophobic film and the preparation method thereof have the following advantages that:

(1) the film prepared by the invention is not attached to any substrate, has super-hydrophobicity and good electrothermal effect, also has intelligent temperature-sensitive color change, and belongs to a multifunctional composite material.

(2) The prepared electrochromism super-hydrophobic film can respond to different temperatures according to user requirements, can realize reversible transformation of any three colors, is rich in aesthetic feeling and plays a role in indicating the ambient temperature.

(3) The super-hydrophobicity of the prepared electrochromism super-hydrophobic film can endow the film with self-cleaning performance, so that impurities on the surface of the film can be easily removed under the flushing of water, the color of the film is bright, and the super-hydrophobicity of the film can prevent the discoloration performance of the film from being damaged in the environments of humidity, acid and alkali and the like for long-term use. Meanwhile, the color change of the film at different temperatures can simply judge the current temperature range, and the method has important application value in the fields of warehouse supervision, reaction devices and the like.

Drawings

Fig. 1 is a schematic structural view of an electrochromic superhydrophobic film prepared in example 1.

FIG. 2 is a graph showing the surface temperature of the electrochromic superhydrophobic film prepared in example 1 as a function of the time of energization.

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

0.2g of graphene oxide (prepared according to the modified Hummers method, Marcano DC, Kosynkin DV, Berlin JM, Sinitskii A, Sun Z, Slesarev A, Alemany LB, Lu W, Tour JM. ACS Nano, 2010, 4: 4806-; and then adding 4g of hydrogen iodide into 10g of acetic acid, uniformly mixing, then adding the graphene oxide film, reducing for 20min at the temperature of 60 ℃, finally repeatedly washing with water and methanol, and drying to obtain a reduced graphene oxide (rGO) film, and bonding fine copper sheets serving as electrodes on two sides of the front surface of the rGO film through conductive silver paste.

Then, 3g of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) was added to 10g N, N-dimethylformamide, stirred at 50 ℃ for 8h, and the solution was drop-coated onto the front side of rGO film and dried at room temperature for 24 h.

Finally, 5g of PVDF-HFP is added into 100g of acetone, the mixture is stirred for 5 hours at 30 ℃, 0.25g of red-yellow discoloration microcapsules (Shenzhen Shenqi New Material science and technology Limited, Red-yellow discoloration color temperature capsules mean that the color is changed from red to yellow) with the discoloration temperature of 45 ℃ are added, and ultrasonic dispersion is carried out for 5 minutes to prepare the dispersion liquid 1. Adding 5g of PVDF-HFP into 100g of acetone, stirring at 30 ℃ for 5h, adding 0.75g of blue-nondiscolouring microcapsule (Shenzhen Shenzhong Qianhromen new material science and technology Co., Ltd.) with a discoloring temperature of 31 ℃, and performing ultrasonic dispersion for 5min to obtain a dispersion liquid 2. Spraying the dispersion liquid 1 and the dispersion liquid 2 to the reverse side of the rGO film in sequence, wherein the working pressure in the spraying parameters is 0.2MPa, the distance between a spray gun and the rGO film is 10cm, and the spraying dosage and the flow of the dispersion liquid 1 are 0.3 mL-cm respectively^-2And 0.3mL · s^-1The amount of the dispersion 2 sprayed and the flow rate were 0.1mL cm^-2And 0.15mL · s^-1. Drying for 3h at room temperature to obtain the electrochromism super-hydrophobic film.

Fig. 1 is a schematic structural diagram of an electrochromic super-hydrophobic film prepared in this example. As can be seen in fig. 1, the film includes, from top to bottom, a blue-no low temperature coloration layer, a red-yellow high temperature coloration layer, an rGO electrothermal layer, and a PVDF-HFP substrate layer. The contact angle of the electrochromism super-hydrophobic film prepared by the embodiment is 155 degrees, and the electrochromism super-hydrophobic film has excellent hydrophobicity. This is mainly because the discoloration microcapsules are accumulated on the surface of the film to form a hierarchical coarse structure along with the great volatilization of the solvent during the spraying process, and PVDF-HFP endows the film with extremely low surface energy.

In order to evaluate the electrothermal effect of the electrochromic superhydrophobic film prepared in this example, a voltage of 6V was applied to the film, and the surface temperature thereof was measured with respect to the time of energization using a Ti200 infrared thermometer of Fluke corporation, usa, and the results thereof are shown in fig. 2. As can be seen from fig. 2, as the energization time was increased to 40s, the film surface temperature rapidly increased to 53 ℃. When the voltage is removed, the surface temperature of the film is gradually recovered. The super-hydrophobic film shows blue color at room temperature, and the low-temperature color changing layer changes from blue color to colorless color as the surface temperature rises to 31 ℃, and the film changes to red color of the high-temperature color changing layer. When the surface temperature was further increased to 45 c, the high temperature discoloration layer changed from red to yellow, and thus the film also showed yellow. When the voltage is removed, the film achieves a reverse blue-red-yellow transition as the surface temperature decreases.

The invention provides an electrochromic super-hydrophobic film and a preparation method thereof by combining an rGO (red graphene oxide) electric heating layer with a substrate layer and an electrochromic super-hydrophobic layer. The rGO is low in price, large-area production is easy to realize by a spraying method, the prepared electrochromism super-hydrophobic film has an excellent electrothermal effect, the surface temperature is quickly increased under low voltage, the three colors are changed, the original color can be reversibly restored after the voltage is removed, and the film has a wide application prospect in the aspects of self-cleaning, daily decoration, environmental temperature indicators and the like. Most of the super-hydrophobic materials reported at present only have a single hydrophobic function, and the application of the super-hydrophobic materials is limited in the aspects of self-cleaning, drag reduction and the like, so that the use requirements of emerging fields are difficult to meet. The super-hydrophobic film prepared by the invention is not limited by a substrate material, and the intelligent temperature-sensitive color-changing performance is introduced, and can be realized by electric heating. The super-hydrophobicity of the surface of the film can endow the film with excellent self-cleaning performance, so that impurities on the surface of the film can be easily removed under water flushing, the bright color of the film is further ensured, and the super-hydrophobicity of the film can prevent the color-changing performance of the film from being damaged when the film is used in environments such as humidity, acid and alkali for a long time. Meanwhile, the multiple color-changing property of the super-hydrophobic film can endow the film with beautiful appearance, can make simple judgment on the temperature range of the current environment, has important application value in the fields of reaction devices, storehouse supervision and the like, and greatly widens the application of the super-hydrophobic film in intelligent materials.

Example 2

Dispersing 0.4g of graphene oxide in 100g of water, uniformly performing ultrasonic treatment, dripping the graphene oxide on glass treated by oxygen plasma, and drying the glass at 50 ℃ for 12 hours; then adding 2g of hydrogen iodide into 10g of acetic acid, uniformly mixing, then adding a graphene oxide film, reducing for 30min at 50 ℃, finally repeatedly washing with water and methanol, and drying to obtain a rGO film, and bonding fine copper sheets serving as electrodes on two sides of the front surface of the rGO film through conductive silver paste; then, 3g of hydrogenated styrene-butadiene-styrene (SEBS) was added to 20g N-methyl pyrrolidone, stirred at 100 ℃ for 3h, and the solution was drop-coated onto the front of rGO film and dried at room temperature for 24 h.

Finally, 5g of SEBS is added into 71g of toluene, stirred for 3h at 50 ℃, then 0.5g of blue-violet color-changing microcapsules with the color-changing temperature of 80 ℃ are added, and ultrasonic dispersion is carried out for 5min, thus obtaining the dispersion liquid 1. Similarly, 1.5g of black-non-discoloring microcapsules having a discoloring temperature of 45 ℃ were added to the solution of SEBS prepared above dispersed in toluene, and ultrasonically dispersed for 5min to prepare a dispersion 2. Spraying the dispersion liquid 1 and the dispersion liquid 2 to the reverse side of the rGO film in sequence, wherein the working pressure in the spraying parameters is 0.4MPa, the distance between a spray gun and the rGO film is 20cm, and the spraying dosage and the flow of the dispersion liquid 1 are 0.5 mL-cm respectively^-2And 0.5mL · s^-1The amount of the dispersion 2 sprayed and the flow rate were 0.2mL cm^-2And 0.3mL · s^-1. Drying for 6h at room temperature to obtain the electrochromism super-hydrophobic film.

The contact angle of the electrochromism super-hydrophobic film prepared in the embodiment is 160 degrees, the surface temperature is raised to 97 ℃ within 40s under the voltage of 10V, and the film realizes the black-blue-purple discoloring process.

Example 3

Dispersing 0.1g of graphene oxide in 100g of water, uniformly performing ultrasonic treatment, dripping the graphene oxide on glass treated by oxygen plasma, and drying the glass at 50 ℃ for 12 hours; then adding 5g of hydrogen iodide into 10g of acetic acid, uniformly mixing, then putting the graphene oxide film, reducing for 2min at 100 ℃, finally repeatedly washing with water and methanol, and drying to obtain a reduced graphene oxide (rGO) film, and bonding fine copper sheets serving as electrodes on two sides of the front surface of the rGO film through conductive silver paste; then, 3g of styrene-butadiene-styrene block copolymer (SBS) is added into 15g of dimethylacetamide, stirred for 5h at 60 ℃, then the solution is dripped on the front surface of the rGO film, and dried for 24h at room temperature; finally, adding 5g of SBS into 85g of tetrahydrofuran, stirring for 4h at 40 ℃, adding 0.4g of green-purple color-changing microcapsules with the color-changing temperature of 80 ℃, and performing ultrasonic dispersion for 5min to obtain the dispersion liquid 1. Similarly, 1g of red-non-discoloring microcapsules having a discoloring temperature of 65 ℃ were added to the above-prepared SBS dispersed in tetrahydrofuran solution, and ultrasonically dispersed for 5min to prepare a dispersion 2. Spraying the dispersion liquid 1 and the dispersion liquid 2 to the reverse side of the rGO film in sequence, wherein the working pressure in the spraying parameters is 0.3MPa, the distance between a spray gun and the rGO film is 15cm, and the spraying dosage and the flow of the dispersion liquid 1 are 0.4 mL-cm respectively^-2And 0.4mL · s^-1The amount of the dispersion 2 sprayed and the flow rate were 0.15 mL/cm^-2And 0.2mL · s^-1. And drying at room temperature for 5h to obtain the electrochromism super-hydrophobic film.

The contact angle of the electrochromism super-hydrophobic film prepared in the embodiment is 158 degrees, the surface temperature is raised to 87 ℃ within 40s under the voltage of 9V, and the film realizes the red-green-purple discoloring process.

Example 4

Dispersing 0.3g of graphene oxide in 100g of water, uniformly performing ultrasonic treatment, dripping the graphene oxide on glass treated by oxygen plasma, and drying at 40 ℃ for 12 hours; then adding 3g of hydrogen iodide into 10g of acetic acid, uniformly mixing, then adding the graphene oxide film, reducing for 5min at 80 ℃, finally repeatedly washing with water and methanol, and drying to obtain a reduced graphene oxide (rGO) film, and then using conductive silver paste as the materialThin copper sheets of the electrode are bonded on two sides of the front surface of the rGO film; then, 3g of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) is added into 12g N-methyl pyrrolidone, stirred for 5 hours at 70 ℃, then the solution is dripped on the front surface of the rGO film, and dried for 24 hours at room temperature; finally, 5g of PVDF-HFP is added into 90g of acetone, stirred for 3h at 35 ℃, then 0.45g of blue-green-changing microcapsules with the color-changing temperature of 65 ℃ are added, and ultrasonic dispersion is carried out for 5min, so as to prepare the dispersion liquid 1. Similarly, 1.25g of yellow-no-discoloration microcapsule having a discoloration temperature of 45 ℃ was added to the above-prepared PVDF-HFP solution dispersed in acetone, and ultrasonically dispersed for 5min to prepare dispersion 2. Spraying the dispersion liquid 1 and the dispersion liquid 2 to the reverse side of the rGO film in sequence, wherein the working pressure in the spraying parameters is 0.3MPa, the distance between a spray gun and the rGO film is 15cm, and the spraying dosage and the flow of the dispersion liquid 1 are 0.4 mL-cm respectively^-2And 0.5mL · s^-1The amount of the dispersion 2 sprayed and the flow rate were 0.15 mL/cm^-2And 0.3mL · s^-1. Drying for 4h at room temperature to obtain the electrochromism super-hydrophobic film.

The contact angle of the electrochromism super-hydrophobic film prepared in the embodiment is 160 degrees, the surface temperature is raised to 69 ℃ within 40s under the voltage of 8V, and the film realizes a yellow-blue-green discoloring process.

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 super-hydrophobic film of electrothermal discoloration, it is characterized in that, the super-hydrophobic film of described electrothermal discoloration is a composite film, and from top to bottom are respectively low temperature discoloration layer, high temperature discoloration layer, rGO electrothermal heating layer and base layer;

The hydrophobic polymer is added to the organic solvent A, stirred evenly, the obtained solution is drop-coated on the front of the reduced graphene oxide film, and dried at room temperature to obtain a base layer;

The rGO electric heating layer is prepared by the following method: dispersing graphene oxide in water, uniformly ultrasonically applying it to the glass after oxygen plasma treatment, and drying to obtain a GO film; then adding hydrogen iodide into acetic acid Mix evenly, put in GO film and reduce at 50-100 ^o C; wash and dry to obtain reduced graphene oxide film, and then use conductive silver paste to bond fine copper sheets as electrodes on the front of the reduced graphene oxide film. On both sides, the rGO electric heating layer was prepared;

The low-temperature discoloration layer and the high-temperature discoloration layer are prepared by the following methods: adding the hydrophobic polymer into the organic solvent B, adding the high-temperature discoloring microcapsules after stirring, to prepare the dispersion liquid 1; dispersing the hydrophobic polymer in the organic solvent B In the solution, add low temperature discoloration microcapsules to obtain dispersion liquid 2; Dispersion liquid 1 and dispersion liquid 2 are sprayed on the reverse side of the reduced graphene oxide film in turn to form a low temperature discoloration layer and a high temperature discoloration layer;

Described organic solvent A is any one in N,N-dimethylformamide, N-methylpyrrolidone and dimethylacetamide; Described organic solvent B is any one in acetone, toluene and tetrahydrofuran kind.

2. the super-hydrophobic film of electrothermal discoloration according to claim 1, is characterized in that, the super-hydrophobic film of described electrothermal discoloration is 150-160 ^o at room temperature; Voltage, the surface temperature of the film rises to 30-100 ^o C within 40s; the film can achieve three color transformations when heated, and reversibly return to the original color when cooled.

3. the preparation method of the super-hydrophobic film of electrothermal discoloration described in claim 1 or 2, is characterized in that comprising the following steps:

1) In parts by mass, firstly disperse 0.1-0.4 parts of graphene oxide in 100 parts of water, uniformly ultrasonically and then drop-coat on the glass treated with oxygen plasma, and dry to obtain a GO film; 2-5 parts of iodine Hydrogen hydride was added to 10 parts of acetic acid and mixed evenly, then put into the GO film and reduced at 50-100 ^o C; washed and dried to obtain a reduced graphene oxide film, and then the fine copper sheets used as electrodes were bonded by conductive silver paste On both sides of the front face of the reduced graphene oxide, rGO electric heating layers were prepared;

2) Add the hydrophobic polymer to the organic solvent A, stir evenly, drop the obtained solution on the front of the reduced graphene oxide film, and dry at room temperature to obtain a base layer; then add the hydrophobic polymer to the organic solvent B, Stir well, then add high-temperature color-changing microcapsules, and ultrasonically disperse to obtain dispersion 1; disperse the hydrophobic polymer in the solution of organic solvent B, add low-temperature color-changing microcapsules, and ultrasonically disperse to obtain dispersion 2; Liquid 1 and dispersion liquid 2 are successively sprayed on the reverse side of the reduced graphene oxide film to form a multi-level discoloration layer, and the spraying amount depends on the spraying conditions, and is dried at room temperature to obtain an electrothermally discolored superhydrophobic film;

The hydrophobic polymer is any of polyvinylidene fluoride-hexafluoropropylene copolymer, hydrogenated styrene-butadiene-styrene block copolymer and styrene-butadiene-styrene block copolymer. A sort of;

4. the preparation method of the super-hydrophobic film of electrothermal discoloration according to claim 3, is characterized in that: described low-temperature discoloration microcapsule discoloration temperature is ^{31-65 ℃} , and the color change is in color-colorless any one; the discoloration temperature of the high-temperature discoloration microcapsules is 45-80 ^° C, and the color changes to any one of color-color; the particle size of the discoloration microcapsules is 0.5-5 μm.

5. the preparation method of the superhydrophobic film of electrothermal discoloration according to claim 3, is characterized in that: the mass ratio of described hydrophobic polymer and organic solvent A is 3:20-3:10, hydrophobicity The mass ratio of polymer to organic solvent B is 1:25-7:100, the mass ratio of low-temperature color-changing microcapsules to hydrophobic polymer is 3:20-3:10, and the mass ratio of high-temperature color-changing microcapsules to hydrophobic polymer is 1:20-1:10.

6. the preparation method of the superhydrophobic film of electrothermal discoloration according to claim 3, is characterized in that: the working pressure of described spraying is 0.2-0.4MPa, and the spraying distance of spray gun and reduced graphene oxide film is 10 -20cm; the spraying dosage and flow rate of the spraying dispersion 1 are 0.3-0.5mL·cm ^-2 and 0.3-0.5mL·s ^-1 respectively, and the spraying dosage and flow rate of the spraying dispersion 2 are 0.1-0.2mL· cm ^-2 and 0.15-0.3 mL·s ^-1 .

7. The preparation method of electrothermally discolored superhydrophobic thin film according to claim 3, characterized in that: in step 1), the drying temperature of the GO thin film obtained after drying is 30-50 ^℃ , and the time is 12h; the reduction time at 50-100 ^o C is 2-30min; the washing is repeated washing with water and methanol.

8. The method for preparing an electrothermally discolored super-hydrophobic film according to claim 3, wherein in step 2), in the preparation of the base layer, stirring evenly is at 50-100 ^o C for 3 -8h; in the preparation of the dispersion liquid 1, stirring evenly is at 30-60 ^o C for 3-5h; the drying time at room temperature is 3-6h.

9. The method for preparing an electrothermally discolored superhydrophobic film according to claim 3, wherein in step 2), in the preparation of the dispersion liquid 1 and the dispersant 2, the ultrasonic dispersion time is 5 -10min.