Preparation method of HCMT@PPY photothermal superhydrophobic composite material

Abstract

Preparation and Application of a HCMT@PPY Photothermal Superhydrophobic Composite Material. The preparation method first obtains hollow microtubes (HCMT) with a hollow structure by simple carbonization without a template, and in-situ polymerizes polypyrrole (PPy) onto the surface of HCMT. Finally, hydrophobic grafting is carried out with organochlorosilane to prepare a photothermal superhydrophobic HCMT@PPY coating. Due to the synergistic photothermal conversion performance of HCMT and PPy and the hollow structure reducing heat loss during the photothermal conversion process, the coating exhibits excellent photothermal heating characteristics and excellent superhydrophobic self-cleaning performance, thus realizing the synergistic reduction of ice hazards by superhydrophobic anti-icing and photothermal de-icing. The HCMT@PPY sample has excellent mechanical stability and chemical stability. The excellent environmental adaptability can greatly extend the service life of the coating and meet the long-term use conditions. In addition, the raw materials required for the preparation do not contain harmful substances and are non-toxic and pollution-free.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface functional composite materials, and particularly relates to a preparation method of an HCMT@PPY photothermal superhydrophobic composite material. Background Art

[0002] Ice formation is a very common natural phenomenon in low-temperature environments. It is a solid-liquid phase change process in which liquid water supercools on a solid surface to form ice crystals and grow. Under different meteorological conditions, ice formation can take various forms such as snow and rime, creating magnificent and beautiful wonders for nature. However, the large accumulation of ice creates many difficulties in daily life and even threatens people's lives and safety. For example, in the power grid system, the large accumulation of ice greatly increases the weight of transmission wires and towers, resulting in wire breaks. The icing and collapse of long-distance transmission lines lead to power communication interruptions, causing significant economic losses to the power grid. In the power generation system, the aerodynamic performance of the blades is affected by icing. On the one hand, it will cause blade overload and uneven blade load distribution, thereby greatly affecting the continuously generated wind energy. On the other hand, when the blades rotate, it is very easy to have operating accidents caused by the shedding of ice cubes. In the northwest region, the icing on the surface of photovoltaic panels will seriously affect the absorption and conversion of solar energy, having a huge impact on their long-term service. In addition, in air transportation, the icing of the engine intake system will cause distortion of the engine inlet flow field, blockage of the intake passage, and deterioration of the engine performance. If the ice cubes shed from the wing or the engine intake system are inhaled by the engine, they will damage the internal blades of the engine, causing mechanical damage. Once the aircraft sensors are iced, the flight crew cannot obtain accurate flight parameters, leading to misoperations of the aircraft's automatic control system. The icing of the aircraft during flight seriously endangers the safe flight of the aircraft.

[0003] In recent years, inspired by the "lotus effect", the hydrophobic principle of superhydrophobic materials has been continuously improved by researchers. People's earliest understanding of the superhydrophobic phenomenon started from lotus leaves. The superhydrophobicity of lotus leaves is manifested in that the surface of lotus leaves looks very fresh and clean after rain. Yuan et al. used a template with a concave array structure on the surface. First, the Kevlar hydrogel solution was shaped by the template method, and then its surface microstructure was solidified by the phase inversion method. Then, it was added to the oxidation solution of MPD and CuSO4 for solution oxidation. In this way, a hydrogel photothermal material was prepared by modification (CN116120746A). However, the preparation process of these photothermal composite materials is relatively complex, seriously restricting their large-scale preparation and application. Zhang et al. pretreated the fabric in a NaOH solution, soaked the pretreated fabric in an activation solution containing nickel to obtain an activation layer of metallic nickel on the surface, then soaked the fabric in an alkaline nickel plating solution containing nickel for surface nickel plating, and finally evenly sprayed a mixed solution of PMHS and ink on the surface to prepare a superhydrophobic fabric for anti-icing and photothermal de-icing (CN115161992A). Maghsoudi, K. et al. studied the anti-icing performance of various superhydrophobic surfaces under different conditions. Through centrifugal adhesion force and push-off tests, a quantitative comparison of the ice adhesion strength of the produced surfaces was provided. The results showed that during the freezing / de-icing cycle, the properties of the material deteriorated, and the rough micro-nano structure on the surface was gradually damaged, resulting in the gradual loss of protective properties such as anti-icing (Journal of Materials Processing Technology, 2021, 288). At present, a large number of achievements have been made in the theoretical research on superhydrophobic surfaces, but there are not many preparation methods, and most of the preparation methods have problems such as harsh experimental conditions, cumbersome steps, and high costs. The superhydrophobic materials already on the market also have disadvantages such as low strength of the surface micro-structure, easy aging, easy wear, and short service life. Moreover, there are very few materials with photothermal superhydrophobic properties on the market, and there are also problems such as poor photothermal performance, easy pollution, and high energy consumption.

[0004] To solve the above problems, the HCMT@PPY photothermal superhydrophobic composite material has been developed. Biomass materials are green, non-toxic, and low-cost materials. After carbonization, carbon materials with excellent photothermal properties can be obtained, which can be used for efficient solar energy absorption. This material endows superhydrophobic materials with the ability of solar photothermal conversion synergy to prepare superhydrophobic photothermal materials, becoming an emerging anti-icing and de-icing technology. The superhydrophobic surface can utilize its own superhydrophobic characteristics to reduce the adhesion of water on the surface, extend the icing time, and play a passive anti-icing function; at the same time, the photothermal conversion function can absorb solar energy and convert light energy into heat energy to play an active de-icing function.

[0005] To overcome the deficiencies of the above-mentioned existing technologies, the purpose of the present invention is to provide a preparation method of HCMT@PPY photothermal superhydrophobic composite materials. Using easily available absorbent cotton as the raw material, an HCMT@PPY photothermal superhydrophobic composite material is prepared and applied to the field of superhydrophobic photothermal composite materials to solve the disadvantages of existing materials containing toxic substances, causing large pollution, having single functional characteristics, and high energy consumption of existing de-icing technologies.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions.

[0007] A preparation method of biomass-based HCMT@PPY photothermal superhydrophobic composite materials, characterized by comprising the following steps:

[0008] Step 1: Place the absorbent cotton in a porcelain boat and put it in a high-temperature and high-pressure tubular furnace for carbonization. The temperature of the tubular furnace is 400 - 800 °C, the carbonization time is 2 h, and then it is placed in a nitrogen atmosphere furnace to cool naturally to room temperature;

[0009] Step 2: Add the carbonized HCMT and deionized water into a beaker and ultrasonically form a uniform HCMT. The ultrasonic time is 30 min;

[0010] Step 3: Under mechanical stirring, add Py (pyrrole) into the above-mentioned HCMT dispersion liquid, and add a certain amount of oxidants such as ammonium persulfate and ferric chloride. After reacting for 1 - 10 h, centrifuge to obtain HCMT@PPY.

[0011] Step 4: Ultrasonically disperse the above-mentioned HCMT@PPY powder in ethyl acetate and ethanol (volume ratio 1:1), add organochlorosilane for modification, and after the reaction, spray or dip-coat it on the substrate. After curing, an HCMT@PPY photothermal superhydrophobic composite material is obtained. The curing temperature is 60 - 120 °C, and the curing time is 1 - 5 h.

[0012] The absorbent cotton, cotton fiber, etc. in Step 1 are carbonized by a one-step carbonization method to obtain black biomass non-crystalline carbon.

[0013] The concentration of HCMT in Step 2 is 2 - 10 mg / mL.

[0014] The concentration of Py in Step 3 is 10 - 50 mg / mL. The oxidant is one of ammonium persulfate and ferric chloride, and its mass ratio to Py is 8:1.

[0015] The concentration of HCMT@PPY in Step 4 is 8 mg / mL. The organochlorosilane is dimethyldichlorosilane, methyltrichlorosilane, propyltrichlorosilane, etc., with a concentration of 10 - 50 mg / mL, and the reaction time is 1 - 5 h.

[0016] In step 4, the base materials include glass, wood, fabric, metal, sponge, plastic, etc.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention discloses a preparation method of HCMT@PPY photothermal superhydrophobic composite material. In this preparation method, first, absorbent cotton is placed in a porcelain boat and carbonized in a high-temperature and high-pressure tube furnace, and then it is placed in a nitrogen atmosphere furnace to cool naturally to room temperature. Then, the carbonized HCMT and ionic water are added to a beaker, and ultrasonic treatment is carried out to form a uniform HCMT, and it is added to PY (pyrrole) under mechanical stirring for reaction, and then oxidized by an oxidant and centrifuged. After centrifugation, it is dispersed in a mixed solution of ethyl acetate and ethanol, and organochlorosilane is added for modification. Finally, it is sprayed or dip-coated on a base material, and after curing, the HCMT@PPY photothermal superhydrophobic composite material is obtained. The rough surface structure of the coating and the rich low-surface-energy substances act synergistically to provide the basis for the superhydrophobicity of the coating. The outstanding self-cleaning performance of the superhydrophobic surface is expected to remove stains on the surface and extend the service life of the photothermal coating. Compared with traditional coating materials, this coating has a wide absorption range for the spectrum, more than 96% in the visible light wavelength range. The HCMT@PPY coating can rapidly heat up under 1kW / m 2 irradiation, and the equilibrium temperature reaches 96.6°C. The coating has an interconnected porous micro-nano structure and high adhesion. In addition, in the anti-icing and de-icing test, on the glass sheet coated with the HCMT@PPY coating, the freezing time of water droplets is extended by 4 times, and the ice layer completely melts within 500s, showing excellent superhydrophobic self-cleaning performance, thus realizing the synergistic reduction of the harm of ice by superhydrophobic anti-icing and photothermal de-icing. This photothermal superhydrophobic coating can simultaneously achieve the functions of active de-icing and passive anti-icing, and has excellent superhydrophobic, photothermal, durable, stable and self-healing properties, and can effectively complete long-term surface protection work. The spraying construction has high efficiency and good uniformity, and has a wide range of application fields, including transportation, wind turbine blades, aircraft wings, etc. Brief Description of the Drawings

[0019] Figure 1 are the analysis and test spectrograms of the materials prepared by the present invention and other materials;

[0020] Among them, (a) is the XPS spectrogram of the HCMT@PPY coating; (b) is the Fourier infrared spectrogram of cotton fiber, HCMT and HCMT@PPY coating; (c) is the XRD spectrogram of cotton fiber, HCMT and HCMT@PPY coating;

[0021] Figure 2 are the silver mirror phenomenon, coating floating phenomenon and water droplet hydrophobic phenomenon of the materials prepared by the present invention;

[0022] Among them, (a) shows the silver mirror phenomenon of the coated fabric; (b) shows that the coated fabric can float on the surface of the methylene blue solution, while the bare fabric will sink; (c) shows that water droplets can stand freely on the sample powder.

[0023] Figure 3 are the heating curves and photothermal imaging photos of the materials prepared by the present invention under different sunlight irradiations;

[0024] Among them, (a) shows the heating curve; (b) shows the photothermal imaging picture;

[0025] Figure 4 are the photos of the anti-icing and de-icing processes of the materials prepared by the present invention;

[0026] Figure 5 is the self-cleaning performance of the materials prepared by the present invention at room temperature. Specific Embodiments

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to the following embodiments:

[0028] A preparation method of an HCMT@PPY photothermal superhydrophobic composite material, characterized by comprising the following steps:

[0029] (Step 1, Place the absorbent cotton in a porcelain boat and place it in a high-temperature and high-pressure tube furnace for carbonization. The temperature of the tube furnace is 400 - 800 °C, and the carbonization time is 2 h. Then, place it in a nitrogen atmosphere furnace and let it cool naturally to room temperature;

[0030] Step 2, Add the carbonized HCMT and deionized water to a beaker and ultrasonically form a uniform HCMT. The ultrasonic time is 30 min;

[0031] Step 3, Under mechanical stirring, add Py (pyrrole) to the above-mentioned HCMT dispersion liquid, and add a certain amount of oxidants such as ammonium persulfate and ferric chloride. After reacting for 1 - 10 h, centrifuge to obtain HCMT@PPY.

[0032] Step 4, Ultrasonically disperse the above-mentioned HCMT@PPY powder in ethyl acetate and ethanol (volume ratio 1:1), add organochlorosilane for modification, and after the reaction, spray or dip-coat it on the substrate. After curing, an HCMT@PPY photothermal superhydrophobic composite material is obtained. The curing temperature is 60 - 120 °C, and the curing time is 1 - 5 h.

[0033] Example 1

[0034]

[0035] Place the absorbent cotton in a porcelain boat and place it in a high-temperature and high-pressure tube furnace for carbonization. The temperature of the tube furnace is 400 °C, and it is carbonized in a nitrogen atmosphere for 2 h and then naturally cooled to room temperature; add 5 mg / mL HCMT to 30 mL of deionized water and ultrasonically form a uniform HCMT dispersion. Under mechanical stirring, add 25 mg / mL Py to the above HCMT dispersion, and add 6 g of ferric chloride. After reacting for 8 h, centrifuge to obtain HCMT@PPY.

[0036] Ultrasonically disperse 8 mg / mL of the above HCMT@PPY powder in ethyl acetate and ethanol (volume ratio 1:1), add 20 mg / mL of dimethyldichlorosilane for modification, and react for 2 h; after the reaction, spray or dip-coat on the substrate and cure at 100 °C for 1 h to obtain the HCMT@PPY photothermal superhydrophobic composite material. As Figure 1 (a) shows, perform XPS testing to study the chemical composition of its surface. In the HCMT@PPY coating, peaks of C, O, and Si contents can be clearly seen. The finally prepared HCMT@PPY coating has a large number of low-surface-energy substances and a hierarchical rough structure, and the two together achieve the excellent superhydrophobic performance of the coating. As Figure 1 (b) shows, test the FT-IR spectra of cotton fiber, HCMT, and HCMT@PPY samples. In the curve of cotton fiber, the characteristic peak of ester group stretching vibration and the characteristic peak of O-H on the surface of HCMT can be clearly seen, but its intensity is greatly reduced compared with that of cotton fiber. The number of oxygen-containing groups on the surface of the HCMT@PPY photothermal superhydrophobic coating is very small, indicating that the HCMT@PPY coating has excellent superhydrophobic performance. The XRD patterns of cotton, HCMT, and HCMT@PPY samples are as Figure 1 (c) shows. The XRD results confirm that the prepared sample is a carbon material. In addition, the diffraction peaks in the HCMT@PPY spectrum are attributed to PPY, indicating that the sample is a composite of HCMT and PPY. Therefore, from the above results, it can be seen that HCMT and HCMT@PPY are successfully prepared.

[0037] Example 2

[0038]

[0039]

[0040] Place the absorbent cotton in a porcelain boat and put it in a high-temperature and high-pressure tube furnace for carbonization. The temperature of the tube furnace is 500 °C, and it is carbonized in a nitrogen atmosphere for 2 h and then naturally cooled to room temperature. Add 4 mg / mL HCMT to 20 mL of deionized water and ultrasonically form a uniform HCMT dispersion. Under mechanical stirring, add 20 mg / mL Py to the above HCMT dispersion, and add 3.2 g of ferric chloride and react for 5 h, then centrifuge to obtain HCMT@PPY.

[0041] Ultrasonically disperse 8 mg / mL of the above HCMT@PPY powder in ethyl acetate and ethanol (volume ratio 1:1), add 15 mg / mL of dimethyldichlorosilane for modification, and react for 3 h; after the reaction, spray or dip-coat it on the substrate and cure it at 90 °C for 2 h to obtain the HCMT@PPY photothermal superhydrophobic composite material. As Figure 2 shown, when the material is immersed in water, an obvious silver mirror phenomenon can be observed. A fabric sprayed with an HCMT@PPY coating on one side can stably float on the methylene blue water surface, forming a concave groove around the fabric under gravity, while an ordinary fabric will completely sink in the water. Water droplets can stand freely on the sample powder, with a large contact angle, which indicates that the coating has excellent superhydrophobic properties.

[0042] Example 3

[0043]

[0044] Place the absorbent cotton in a porcelain boat and put it in a high-temperature and high-pressure tube furnace for carbonization. The temperature of the tube furnace is 600 °C, and it is carbonized in a nitrogen atmosphere for 2 h and then naturally cooled to room temperature. Add 6 mg / mL HCMT to 30 mL of deionized water and ultrasonically form a uniform HCMT dispersion. Under mechanical stirring, add 30 mg / mL Py to the above HCMT dispersion, and add 7.2 g of ferric chloride and react for 6 h, then centrifuge to obtain HCMT@PPY.

[0045] Ultrasonically disperse 8 mg / mL of the above HCMT@PPY powder in ethyl acetate and ethanol (volume ratio 1:1), add 20 mg / mL of methyltrichlorosilane for modification, and react for 4 h; after the reaction, spray or dip-coat it on the substrate and cure it at 100 °C for 1 h to obtain the HCMT@PPY photothermal superhydrophobic composite material. As Figure 3 shown, the photothermal performance of the prepared material was tested. It can be seen that under different light intensity conditions, the coated fabric can be heated to different temperatures, and as the light intensity gradually increases, the highest temperature also rises. Among them, under 1 sun, the material temperature rises rapidly and quickly reaches 92.5 °C within 60 s. The excellent photothermal performance provides a prerequisite for photothermal de-icing.

[0046] Example 4

[0047]

[0048] Place the absorbent cotton in a porcelain boat and place it in a high-temperature and high-pressure tube furnace for carbonization. The temperature of the tube furnace is 700 °C, and it is carbonized in a nitrogen atmosphere for 2 h and then naturally cooled to room temperature; add 8 mg / mL HCMT to 40 mL of deionized water and ultrasonically form a uniform HCMT dispersion. Under mechanical stirring, add 30 mg / mL Py to the above HCMT dispersion, and add 9.6 g of ferric chloride. After reacting for 7 h, centrifuge to obtain HCMT@PPY.

[0049] Ultrasonically disperse 8 mg / mL of the above HCMT@PPY powder in ethyl acetate and ethanol (volume ratio 1:1), add 25 mg / mL of methyltrichlorosilane for modification, and react for 2 h; after the reaction, spray or dip-coat it on the substrate, and cure it at 110 °C for 1 h to obtain the HCMT@PPY photothermal superhydrophobic composite material. As Figure 4 shown, the anti-icing and photothermal de-icing performance of the prepared material was tested. At -20 °C, at 31 s, the water droplets on the surface of the bare glass slide began to freeze, and there was a relatively obvious boundary between the growing ice and water. At 65 s, the water droplets were completely frozen. Compared with the water droplets on the glass slide sprayed with the coating, the time when the water droplets began to freeze was 123 s, and the time when they were completely frozen was 265 s, which was about 4 times that of the bare glass slide. This shows that the HCMT@PPY coating can significantly extend the icing time of water droplets. In addition, in the photothermal de-icing test, an ice layer with a thickness of 2 mm was formed on the surface of the HCMT@PPY coating to simulate icing. Under the irradiation of a solar light intensity, due to the photothermal synergy of HCMT and PPY, the surface temperature of the coating rapidly increased. After 90 s, the ice layer began to melt. Due to the existence of the micro-nano structure and low surface energy on the surface of the HCMT@PPY coating, the small water droplets formed by the melting ice could not remain on the coating surface and rolled off under the action of gravity. After 500 s, the entire ice layer turned into droplets and rolled off from the surface, proving that the coating can achieve de-icing without consuming external energy, showing excellent active de-icing performance.

[0050] Example 5

[0051]

[0052]

[0053] Place absorbent cotton in a porcelain boat and put it in a high-temperature and high-pressure tube furnace for carbonization. The temperature of the tube furnace is 800 °C, and it is carbonized for 2 h in a nitrogen atmosphere and then naturally cooled to room temperature; Add 10 mg / mL HCMT to 50 mL of deionized water and ultrasonically form a uniform HCMT dispersion. Under mechanical stirring, add 30 mg / mL Py to the above HCMT dispersion, and add 12 g of ferric chloride. After reacting for 8 h, centrifuge to obtain HCMT@PPY.

[0054] Ultrasonically disperse 8 mg / mL of the above HCMT@PPY powder in ethyl acetate and ethanol (volume ratio 1:1), add 25 mg / mL of propyltrichlorosilane for modification, and react for 5 h; After the reaction, spray or dip-coat it on the substrate, and cure it at 80 °C for 2 h to obtain the HCMT@PPY photothermal superhydrophobic composite material. As Figure 5 shown, test the self-cleaning performance of the coating. Place the glass slide coated with the HCMT@PPY coating at an inclined angle and randomly scatter solid particle pollutants on the surface. Then pour water onto the contaminated coating surface, and the water droplets immediately roll off the surface, taking the pollutants encountered during the rolling process away from the coating surface. After the test, there is no pollutant residue on the coating surface. The superhydrophobic coating surface has a low surface energy and a rough structure, making the coating show excellent self-cleaning performance.

[0055] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of HCMT@PPY photothermal superhydrophobic composite material, characterized in that, The following steps are involved: Step 1: Place the absorbent cotton in a porcelain boat and place it in a high-temperature and high-pressure tube furnace for carbonization at a temperature of 400-800°C for 2 hours, then place it in a nitrogen atmosphere furnace and naturally cool it to room temperature; Step 2: Add the carbonized HCMT and deionized water into a beaker and ultrasonicate to form a uniform HCMT for 30 minutes; Step 3: Py pyrrole is added to the above HCMT dispersion under mechanical stirring, and a certain amount of ammonium persulfate and ferric chloride oxidant are added. After reacting for 1-10 hours, centrifugation is performed to obtain HCMT@PPY. Step 4: ultrasonically disperse the HCMT@PPY powder into ethyl acetate and ethanol at a volume ratio of 1:1, add organochlorosilane for modification, spray or dip coat the powder on a substrate after the reaction, and cure the powder to obtain a HCMT@PPY photothermal superhydrophobic composite material at a curing temperature of 60-120°C and a curing time of 1-5 hours. In step 2, the HCMT concentration is 2-10 mg / mL; In step 3, the concentration of Py is 10-50 mg / mL, and the oxidant is one of ammonium persulfate and ferric chloride, with a mass ratio of ammonium persulfate to Py of 8:1; In step 4, the concentration of HCMT@PPY is 8 mg / mL, the organochlorosilane is dimethyldichlorosilane, methyltrichlorosilane or propyltrichlorosilane, the concentration is 10-50 mg / mL, and the reaction time is 1-5 h.

2. The preparation method of a HCMT@PPY photothermal superhydrophobic composite material according to claim 1, characterized in that, The absorbent cotton in step 1 is carbonized by a one-step carbonization method to obtain black biomass amorphous carbon.

3. The method for preparing a HCMT@PPY photothermal super-hydrophobic composite material according to claim 1, wherein In step 4, the substrate is glass, wood, fabric, metal, sponge or plastic.

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