Multifunctional super-hydrophobic photothermal / electrothermal dual-responsive polyaniline@cof modified fabric material and preparation and application thereof

Abstract

This invention discloses a multifunctional superhydrophobic photothermal / electrothermal dual-response polyaniline@covalent organic framework (PANI@COF) modified fabric material, its preparation method, and its applications. The material uses ordinary fabric as a substrate, and a COF interlayer formed by the condensation of 1,3,5-tris(4-aminophenyl)benzene and 2,5-divinyl terephthalaldehyde is grown in situ on the fiber surface via a Schiff base reaction. Utilizing the high specific surface area and abundant active sites of COF, a uniform nucleation and growth platform is provided for polyaniline, effectively inhibiting polyaniline aggregation. Subsequently, a polyaniline layer is coated onto the COF surface through oxidative polymerization, and finally, hydrophobic modification with polydimethylsiloxane (PDMS) yields a superhydrophobic composite material with a micro-nano rough structure, low surface energy, broad-spectrum light absorption, and excellent photothermal / electrothermal conversion properties. The material has a water contact angle of 151.4° and can rapidly heat to 72.5°C and 80.7°C under one solar radiation intensity or a 10V DC voltage drive, respectively. It also features self-cleaning, photothermal / electrothermal de-icing, oil-water separation, photothermal-driven water evaporation, and high-viscosity crude oil adsorption and recovery functions. The invention has a simple preparation process, broad substrate applicability, and is suitable for applications such as outdoor equipment anti-icing and de-icing, self-cleaning, solar water evaporation, and oily wastewater treatment.

Description

Technical Field

[0001] This invention relates to the field of environmental functional materials and new energy application technology, specifically to a fabric material with superhydrophobic self-cleaning, photothermal conversion and electrothermal conversion properties, its preparation method, and the application of the material in surface self-cleaning, anti-icing and de-icing, oil-water separation, water evaporation and crude oil adsorption. Background Technology

[0002] With the rapid growth of global energy demand, crude oil, as a major fossil fuel, is widely extracted and used. However, frequent oil spills during offshore oil exploration and transportation pose a serious threat to the marine ecosystem and human health and safety. Existing oil spill treatment methods (chemical dispersants, in-situ combustion, mechanical skimming, microbial degradation, etc.) have some effectiveness, but they generally suffer from limitations such as high resource costs, long treatment cycles, and the potential for secondary pollution. Furthermore, icing problems on roads, rooftops, and power lines in cold regions severely impact traffic operations and public safety. Traditional chemical de-icing easily leads to environmental pollution, while mechanical de-icing may damage equipment, and neither method achieves long-term, efficient, and environmentally friendly de-icing effects. Therefore, developing multifunctional materials that can simultaneously address oil spill recovery and de-icing issues has become an important research direction.

[0003] In recent years, the strategy of generating localized high temperatures under sunlight using photothermal materials has provided a new approach for the adsorption and active de-icing of high-viscosity crude oil. However, existing photothermal adsorption materials have limited functionality and cannot simultaneously meet the needs of multiple scenarios such as oil-water separation, self-cleaning, and anti-icing / de-icing. Polyaniline (PANI), as a typical conductive polymer, possesses excellent photothermal conversion, electrothermal conversion capabilities, and electrical conductivity. Furthermore, it is inexpensive and easy to synthesize, making it an ideal functional layer for preparing multifunctional composite materials. However, when PANI is directly loaded onto the surface of fabrics, the strong π-π stacking interaction between PANI molecules easily leads to agglomeration, resulting in discontinuous conductive networks, decreased photothermal / electrothermal performance, and difficulty in controlling the uniformity of the load.

[0004] Covalent organic frameworks (COFs) are a class of crystalline porous organic polymers with advantages such as designable structure, high specific surface area, and abundant active sites, making them ideal carrier materials. Currently, there are no reports on using COFs as an intermediate layer to provide a uniform nucleation and growth platform for PANIs on the surface of ordinary fabric fibers through their porous structure and abundant imine / amino active sites. This would effectively inhibit PANI aggregation, improve loading uniformity, and further, combine with superhydrophobic modification to achieve multifunctional integration such as superhydrophobic self-cleaning, photothermal / electrothermal de-icing, oil-water separation, photothermal-driven water evaporation, and photothermal / electrothermal assisted high-viscosity crude oil adsorption and recovery. Therefore, developing a multifunctional modified fabric material with a simple preparation process, broad substrate applicability, and dual photothermal and electrothermal response properties has significant scientific and application value. Summary of the Invention

[0005] The purpose of this invention is to provide a multifunctional superhydrophobic photothermal / electrothermal dual-response polyaniline@COF modified fabric material and its preparation method, so as to solve the problems of easy agglomeration, uneven loading, single function and dependence on a single energy source in existing materials.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A multifunctional superhydrophobic photothermal / electrothermal dual-response polyaniline@COF modified fabric material is composed of a conventional fabric substrate, a COF interlayer grown in situ on the fiber surface, a polyaniline functional layer coated on the COF, and an outermost hydrophobic modified PDMS layer. The functions of the COF interlayer include: ① providing a high specific surface area and abundant active sites, enabling uniform nucleation of polyaniline monomers; ② utilizing a porous structure to limit excessive growth of polyaniline, inhibiting aggregation, and forming a uniform and dense coating layer; ③ the excellent thermal conductivity of COF, enabling rapid conduction of heat generated by the polyaniline layer under photothermal / electrothermal excitation to the entire material and its surface, improving the thermal response rate and utilization efficiency.

[0008] The preparation method of the material includes the following steps:

[0009] (1) Fabric pretreatment: Ordinary fabrics (cotton, polyester or non-woven fabrics) are ultrasonically cleaned with deionized water and anhydrous ethanol in sequence to remove surface impurities, and dried at 60 ℃ for later use.

[0010] (2) Preparation of COF@ fabric: 1,3,5-tris(4-aminophenyl)benzene and 2,5-divinyl terephthalaldehyde were dissolved in acetonitrile solution at a molar ratio of 2:3 and ultrasonically stirred for 3 minutes at 600 W. The pretreated fabric was added, and glacial acetic acid was added as a catalyst. After ultrasonication for 60 seconds, the reaction was carried out at room temperature for 12 hours to allow COF to grow in situ on the fiber surface. After the reaction was completed, the fabric was washed three times with acetonitrile and ethanol respectively, and dried under vacuum at 60 °C to obtain COF@ fabric.

[0011] (3) Preparation of PANI@COF@ fabric: Aniline and p-toluenesulfonic acid were dissolved in deionized water at a molar ratio of 1:2.5 and sonicated for 10 minutes. The COF@ fabric was immersed in the solution and soaked at room temperature for 30 minutes. Ammonium persulfate (molar ratio of 1:1.2 with aniline) was dissolved in deionized water, sonicated to dissolve, and then slowly added to the above reaction system. The polymerization reaction was carried out at 0 °C in an ice-water bath for 24 hours. The fabric was removed, washed repeatedly with deionized water and ethanol until colorless, and dried under vacuum at 60 °C to obtain PANI@COF@ fabric.

[0012] (4) Hydrophobic modification: Immerse the above fabric in a 1% (w / v) PDMS / n-hexane solution for 5 minutes, then remove it and cure it at 60 °C for 2 hours to obtain the target material.

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

[0014] (1) Using ordinary fabrics as the base, the raw materials are readily available and have good flexibility, making it suitable for large-scale preparation.

[0015] (2) The COF intermediate layer effectively inhibits polyaniline agglomeration by providing uniform nucleation sites and spatial confinement, forming a continuous and uniform conductive / photothermal layer.

[0016] (3) The micro-nano rough structure constructed by PDMS and COF / PANI endows the material with long-lasting superhydrophobicity (water contact angle >151.4°) and can achieve self-cleaning (water droplets roll off and carry away dust).

[0017] (4) Polyaniline gives the material excellent photothermal and electrothermal properties, and can quickly heat up to 72.5 °C and 80.7 °C under 1 solar intensity or 10 V voltage, realizing dual-mode active de-icing.

[0018] (5) The material has the ability to perform efficient oil-water separation, photothermal water evaporation and photothermal / electrothermal crude oil adsorption, and has a wide range of applications. Attached Figure Description

[0019] Figure 1 This is a water contact angle test diagram of the material prepared in Example 1 of the present invention.

[0020] Figure 2 This is a schematic diagram of the self-cleaning process of the material prepared in Example 1 of the present invention.

[0021] Figure 3 This is a schematic diagram of the oil-water separation process for preparing the material in Example 1 of the present invention.

[0022] Figure 4 This is a cyclic test diagram of the oil-water separation efficiency of the material prepared in Example 1 of the present invention.

[0023] Figure 5 This is a temperature rise curve of the material prepared in Example 1 of the present invention under one solar radiation intensity.

[0024] Figure 6 The image shows the electrothermal heating curve of the material prepared in Example 1 of this invention at 10V.

[0025] Figure 7 This is a test image showing the adsorption of high-viscosity crude oil by the material prepared in Example 1 of the present invention under photothermal / electrothermal driving.

[0026] Figure 8 This is a de-icing test diagram of the material prepared in Example 1 of the present invention under photothermal and electrothermal modes.

[0027] Figure 9 This is a test graph showing the water loss rate of the material prepared in Example 1 of the present invention under photothermal conditions. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0029] Example 1

[0030] (1) Fabric pretreatment:

[0031] Cut commercially available cotton fabric into 5 cm × 5 cm pieces, and ultrasonically clean them for 15 minutes each with deionized water and anhydrous ethanol, then dry them at 60°C.

[0032] (2) Preparation of COF@fabric:

[0033] Accurately weigh 0.04 mmol (14 mg) of 1,3,5-tris(4-aminophenyl)benzene and 0.06 mmol (11 mg) of 2,5-divinyl-terephthalaldehyde, dissolve them in 5 mL of acetonitrile aqueous solution, and sonicate at 600 W for 3 minutes. Add pretreated cotton fabric and 1.2 mL of glacial acetic acid, sonicate for 60 seconds, and incubate at room temperature for 12 hours. After the reaction, wash the fabric three times each with acetonitrile and ethanol, and dry under vacuum at 60 °C to obtain COF@ fabric.

[0034] (3) Preparation of PANI@COF@fabric:

[0035] 0.74 g of aniline and 2.74 g of p-toluenesulfonic acid were dissolved in 20 mL of deionized water and sonicated for 10 minutes. The COF@ fabric was then immersed in this solution and soaked at room temperature for 30 minutes. Separately, 2.0 g of ammonium persulfate was dissolved in 20 mL of deionized water, sonicated to dissolve, and then slowly added to the above system. The reaction temperature was controlled at 0 °C in an ice-water bath, and polymerization was carried out for 24 hours. The fabric was then removed, washed repeatedly with deionized water and ethanol until colorless, and dried under vacuum at 60 °C to obtain PANI@COF@ fabric. In this step, the abundant active sites provided by the COF interlayer enabled the uniform nucleation and growth of polyaniline, effectively preventing aggregation.

[0036] (4) Hydrophobic modification:

[0037] The fabric was immersed in a 1% (w / v) PDMS / n-hexane solution for 5 minutes, then removed and cured at 60 °C for 2 hours to obtain the target material.

[0038] Performance testing

[0039] Test Example 1: Wettability Test

[0040] The surface wettability of the material obtained in Example 1 was characterized using a contact angle meter. Its static contact angle with deionized water was measured, and the results are as follows: Figure 1 As shown in the figure. The test results show that the water contact angle of the material surface is 151.4°, indicating that the material has excellent superhydrophobic properties. Further investigation was conducted on the wetting behavior of the material with liquids of different properties. The contact angles of acidic aqueous solution (pH=1), alkaline aqueous solution (pH=13), ferric chloride aqueous solution, and saturated sodium chloride aqueous solution were tested on its surface. The results show that the material maintains a good superhydrophobic state for all of the above solutions, with no significant decrease in the contact angle, indicating that the material has good chemical stability and can withstand the corrosion of acid, alkali, and salt solutions.

[0041] Test Example 2: Self-cleaning performance test

[0042] The self-cleaning performance test results are as follows: Figure 2 As shown, simulated dust was evenly sprinkled onto the surface of the material obtained in Example 1, and then water droplets were allowed to roll on the surface. Observation revealed that the water droplets effectively carried away and removed dust particles from the material surface during the rolling process, restoring the material surface to cleanliness, proving that the material has excellent self-cleaning function.

[0043] Test Example 3: Oil-water separation performance test

[0044] The material obtained in Example 1 was used as a filter membrane and fixed in a self-made oil-water separator for the separation experiment of a mixture of dichloromethane and water. The results are as follows: Figure 3 As shown in the diagram, during the separation process, dichloromethane rapidly permeates through the material, while the aqueous phase is completely blocked above the material, achieving highly efficient oil-water separation. To further evaluate the cyclic stability of the material, a mixture of dichloromethane and water was subjected to 10 consecutive separation cycles under the same conditions, and its separation efficiency was tested after each separation. Figure 4 As shown, after 10 cycles, the material's separation efficiency for dichloromethane remained above 97.8%, indicating that the material has a stable and efficient oil-water separation capability.

[0045] Test Example 4: Photothermal Performance Test

[0046] Under simulated sunlight irradiation conditions, an infrared thermal imager was used to monitor the temperature change of the material surface obtained in Example 1 in real time. The results are as follows: Figure 5As shown in the figure. Tests indicate that within 2 minutes of the onset of light exposure, the material surface temperature rapidly rises to over 72.5℃, demonstrating extremely strong photothermal response capabilities. To further verify the stability of the photothermal conversion performance, the material underwent five light-to-natural cooling cycle tests. The results show that the maximum temperature achievable by the material remained essentially consistent across each cycle, without significant attenuation, indicating that the material's photothermal conversion performance exhibits good stability under repeated use.

[0047] Test Example 5: Electrothermal Performance Test

[0048] The electrothermal properties of the material obtained in Example 1 were tested under DC voltage (applied voltage of 10 V), and the change curve of the material surface temperature over time was recorded. The results are as follows: Figure 6 As shown in the figure. Tests revealed that at 10 V, the material surface temperature could rapidly rise to over 80.7 °C within 60 seconds, demonstrating highly efficient electrothermal conversion capabilities. Subsequent voltage on-off cycle tests showed that the highest temperature achievable by the material surface remained essentially constant after each voltage cycle, indicating that the material's electrothermal conversion performance also possesses excellent cycle stability.

[0049] Test Example 6: Adsorption and Recovery Performance Test of High-Viscosity Crude Oil Driven by Photothermal / Electrothermal Methods

[0050] The material obtained in Example 1 was placed on the surface of high-viscosity crude oil, and its adsorption and recovery capacity for crude oil was investigated using two methods: photothermal drive (irradiation with one solar intensity) and electrothermal drive (application of 10 V voltage). The results are as follows. Figure 7 As shown in the figure. Experiments observed that under light or electricity, the viscosity of crude oil below the heated area of ​​the material decreased significantly with increasing temperature, its fluidity increased, and it was rapidly adsorbed by the material in just 40 seconds. These results indicate that, regardless of whether it is a photothermal or electrothermal mode, this material can effectively reduce crude oil viscosity and achieve efficient adsorption and recovery, demonstrating potential application value in areas such as crude oil spill treatment.

[0051] Test Example 7: De-icing Performance Test

[0052] The material obtained in Example 1 was pre-frozen at an ambient temperature of -10 °C. The frozen surface was then treated using both photothermal (irradiation by one solar intensity) and electrothermal (application of a 10 V DC voltage) methods, with the results as follows. Figure 8 As shown in the figure. Experiments have shown that under light or electricity, the surface temperature of the material rises rapidly, and the ice layer melts and detaches from the material surface in just 30 seconds, indicating that the material can achieve rapid and effective de-icing in both light-heat and electro-heat modes.

[0053] Test Example 8: Water Evaporation Performance Test

[0054] Figure 9 The figures show the water loss rate of PDMS@polyaniline@COF modified fabrics under different light intensities as a function of time. The results show that under no-light conditions, the water loss rate of this fabric decreases most gradually, reaching only approximately -0.5 kg / m² after 60 minutes, indicating extremely weak evaporation performance without external heat drive. Under 1x, 1.5x, and 2x solar irradiance conditions, the water loss rate increases significantly with increasing light intensity; at the same time point, the negative value of the water loss rate is larger, with the 2x solar irradiance group showing the best performance, reaching approximately -2.0 kg / m² after 60 minutes. These data directly demonstrate that PDMS@polyaniline@COF modified fabrics possess excellent photothermal response characteristics and efficient solar vapor evaporation capacity. Increasing light intensity can effectively improve its photothermal conversion and interfacial evaporation efficiency, giving it the potential for stable and efficient operation under different irradiance intensities.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features, without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A multifunctional superhydrophobic photothermal / electrothermal dual-response polyaniline@COF modified fabric material, characterized in that, include: Ordinary fabric base; A covalent organic framework (COF) intermediate layer grown in situ on the surface of the fabric fibers, wherein the COF is formed by the condensation of 1,3,5-tris(4-aminophenyl)benzene and 2,5-divinyl terephthalaldehyde via a Schiff base reaction, the COF intermediate layer having a porous structure and active sites for loading polyaniline; a polyaniline (PANI) functional layer uniformly coated on the COF backbone, the COF layer inhibiting polyaniline aggregation by providing uniform nucleation sites and spatial confinement; and a hydrophobic modified polydimethylsiloxane (PDMS) layer formed on the outermost layer by dip coating.

2. The preparation method of the multifunctional superhydrophobic photothermal / electrothermal dual-response polyaniline@COF modified fabric material according to claim 1, characterized in that, Includes the following steps: (1) Fabric pretreatment: The fabric is washed with water and organic solvent in sequence to remove surface impurities, and then dried for later use; (2) Preparation of COF@ fabric: 1,3,5-tris(4-aminophenyl)benzene and 2,5-divinyl terephthalaldehyde were dissolved in acetonitrile aqueous solution, and after ultrasonic stirring, the pretreated fabric was added. An acetic acid catalyst was added to initiate a Schiff base reaction, and a covalent organic framework was generated in situ on the surface of the fabric fibers to obtain COF@ fabric. (3) Preparation of PANI@COF@ fabric: Aniline and p-toluenesulfonic acid are dissolved in water, ultrasonically homogenized, and then soaked in the COF@ fabric obtained in step (2). Ammonium persulfate aqueous solution is added, and an oxidative polymerization reaction is carried out at low temperature to coat the COF surface with a polyaniline layer to obtain PANI@COF@ fabric. (4) Hydrophobic modification: The PANI@COF@ fabric obtained in step (3) is immersed in polydimethylsiloxane solution for hydrophobic modification, and after being taken out and cured, the multifunctional material is obtained.

3. The method according to claim 2, characterized in that, The molar ratio of 1,3,5-tris(4-aminophenyl)benzene to 2,5-divinyl-terephthalaldehyde in step (2) is 2:

3.

4. The method according to claim 2, characterized in that, The concentration of the acetonitrile solution in step (2) is 90%~95%, the ultrasonic power is 500~700W, and the incubation time at room temperature is 10~24 hours.

5. The method according to claim 2, characterized in that, In step (3), the molar ratio of aniline to p-toluenesulfonic acid is 1:2 to 1:3, and the molar ratio of aniline to ammonium persulfate is 1:1 to 1:1.

5.

6. The method according to claim 2, characterized in that, The oxidative polymerization reaction in step (3) is carried out at a temperature of 0~5℃ and for a reaction time of 20~28 hours.

7. The method according to claim 2, characterized in that, The mass-volume concentration of the polydimethylsiloxane solution in step (4) is 0.5%~2%, the immersion time is 3~10 minutes, the curing temperature is 60~80 ℃, and the curing time is 1~3 hours.

8. The application of the multifunctional superhydrophobic photothermal / electrothermal dual-response polyaniline@COF modified fabric material according to claim 1 in at least one of the following: surface self-cleaning, photothermal / electrothermal de-icing, oil-water separation, oily wastewater purification, photothermal-driven water evaporation, and photothermal / electrothermal-driven high-viscosity crude oil adsorption and recovery.

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