Conductive / photothermal conversion material and preparation method and application thereof
By making the wood porous and filling it with liquid metal, the problem of insufficient electrical conductivity and photothermal conversion properties of wood has been solved, enabling the application of conductive/photothermal conversion materials in electronic devices and construction.
Patent Information
- Application Number
- CN202510903486.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-01
- Publication Date
- 2025-11-04
AI Technical Summary
Traditional wood lacks electrical conductivity and photothermal conversion properties, limiting its application in fields such as thermal management of electronic devices or construction. Liquid metals have poor compatibility and stability in the matrix and are prone to leakage.
By selectively removing lignin and hemicellulose from wood, a porous structure is constructed. Then, using a cellulose nanocrystal-stabilized liquid metal emulsion, combined with vacuum impregnation and hot pressing processes, liquid metal is filled into the wood pores to form a continuous conductive network.
It improves the electrical conductivity and photothermal conversion properties of wood, providing efficient thermal management and temperature regulation capabilities, and is suitable for electronic equipment and building applications.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of composite performance material preparation, in particular to a conductive / photothermal conversion material and a preparation method and application thereof. BACKGROUND
[0002] Wood is a kind of material with abundant resources, which is renewable and biodegradable, and is widely used in building, furniture and fuel, etc. It is generally believed that the cell wall of wood cell is composed of three kinds of high molecular polymers, i.e. lignin, cellulose and hemicellulose, and the cellulose fibrils arranged in order are wrapped in lignin and hemicellulose, and due to this ordered arrangement, wood provides very excellent mechanical properties. However, the traditional wood lacks the properties of electrical conductivity and photothermal conversion, which limits its application in the fields of electronic device thermal management or building, etc.
[0003] Gallium-based liquid metal has good flowability, good electrical conductivity and good biocompatibility, and has broad prospects in the fields of electronic device thermal management and building. However, the liquid metal always maintains a spherical shape, has a large size and a large surface tension, and has poor compatibility with the matrix, which seriously limits the application of gallium-based liquid metal. In addition, direct use of liquid metal is prone to leakage, so it is necessary to seek a stable carrier material. SUMMARY
[0004] The present application aims to at least solve one of the above-mentioned technical problems in the prior art. To this end, one of the objects of the present application is to provide a conductive / photothermal conversion material.
[0005] A second object of the present application is to provide a preparation method of the conductive / photothermal conversion material.
[0006] A third object of the present application is to provide an application of the conductive / photothermal conversion material.
[0007] In order to achieve the above-mentioned objects, the technical solution adopted by the present application is as follows:
[0008] The first aspect of the present application provides a conductive / photothermal conversion material, which is composed of porous wood and liquid metal; the liquid metal is filled in the pore structure of the porous wood in the form of continuous liquid phase.
[0009] In some embodiments of the present application, the porous wood comprises wood treated by lignin and hemicellulose removal.
[0010] In some embodiments of the present application, the wood includes but is not limited to basswood and fir.
[0011] In some embodiments of the present application, the porous wood is prepared by a method comprising the following steps:
[0012] 1) first, using an alkali metal hydroxide solution to heat treat the wood once, removing hemicellulose;
[0013] 2) then, using an oxidizing agent to heat treat the wood again, removing lignin, to obtain the porous wood.
[0014] In some embodiments of the present application, the porous wood is prepared, the concentration of the alkali metal hydroxide solution is 3wt%-7wt%; the temperature of the first heat treatment is 64-96℃, and the time is 4-10h.
[0015] In some preferred embodiments of the present application, the porous wood is prepared, the concentration of the alkali metal hydroxide solution is 4wt%-6wt%; the temperature of the first heat treatment is 72-88℃, and the time is 6-8h.
[0016] In some embodiments of the present application, the alkali metal hydroxide solution comprises a sodium hydroxide solution.
[0017] In some embodiments of the present application, the porous wood is prepared, the concentration of the oxidizing agent is 1wt%-3wt%; the pH of the second heat treatment is 4-5, the temperature is 64-96℃, and the time is 24-48h.
[0018] In some preferred embodiments of the present application, the porous wood is prepared, the concentration of the oxidizing agent is 1.5wt%-2.5wt%; the pH of the second heat treatment is 4-5, the temperature is 72-88℃, and the time is 24-30h.
[0019] In some embodiments of the present application, the oxidizing agent comprises sodium chlorite (NaClO2).
[0020] In some embodiments of the present application, the second heat treatment further comprises using a pH adjuster; the pH adjuster comprises glacial acetic acid.
[0021] In some embodiments of the present application, after the second heat treatment, the process further comprises washing and freeze-drying.
[0022] In some embodiments of the present application, the washing reagent comprises distilled water.
[0023] In some embodiments of the present application, the freeze-drying time is 1-3 days.
[0024] Specifically, the principle of the method for preparing the porous wood of the present application is as follows:
[0025] 1) First, the wood is treated with alkali, and the hemicellulose is connected by β-1, 4-glycosidic bond with various sugar units (such as xylose, mannose), and the following reactions occur under alkaline conditions: ① saponification reaction: alkali metal hydroxide hydrolyzes the acetyl group and glycosidic bond in hemicellulose, which degrades into soluble oligosaccharides or monosaccharides; ② dissolution effect: the alkaline environment destroys the hydrogen bond between hemicellulose and cellulose microfibrils, which is dissolved from the cell wall; heat treatment can accelerate hydrolysis by high temperature, and the concentration of alkali metal hydroxide solution is controlled at 3wt%-7wt%, which can balance the dissolution efficiency and cellulose retention rate, and avoid the degradation of cellulose swelling caused by high concentration;
[0026] 2) Then, the wood with most of the hemicellulose removed is treated with oxidation, and the oxidizing agent destroys the lignin structure under weak acid conditions through oxidation reaction: when the oxidizing agent is sodium hypochlorite (NaClO2), NaClO2 generates chlorous acid (HClO2) and chlorine dioxide (ClO2) under weak acid conditions, ClO2 attacks the phenylpropane unit of lignin and oxidizes it into quinones and water-soluble carboxylic acids, and the β-O-4 ether bond connecting the monomers in lignin is oxidized and broken, resulting in depolymerization; adding a pH adjuster to adjust the pH to 4-5 can ensure the effective generation of ClO2 and avoid strong acid corrosion of cellulose;
[0027] 3) By using the step-by-step treatment method, first removing hemicellulose by alkali treatment and then removing lignin by oxidation treatment, the interference of side reactions can be avoided, and after removing hemicellulose, the porosity of the wood increases, and after removing lignin, the cell wall of the wood becomes thin and the microfibrils are exposed, forming a through multi-level pore channel; in addition, after removing hemicellulose, part of the structure may collapse, so it needs to be fixed by subsequent freeze-drying, and the water content of the wood after chemical treatment is high, direct drying will cause capillary force to cause the collapse of the pore channel, freeze-drying can make the water directly sublimate, avoid the damage of liquid surface tension to the pore structure, and play the role of structure fixation.
[0028] The second aspect of the present application provides a preparation method of the conductive / photothermal conversion material according to the first aspect of the present application, comprising the following steps:
[0029] The porous wood is subjected to liquid metal emulsion vacuum impregnation-freeze drying cycle and hot pressing to obtain the conductive / photothermal conversion material.
[0030] In some embodiments of the present application, the liquid metal emulsion is prepared by a method comprising the following steps:
[0031] The cellulose nanocrystals are mixed with water to form a dispersion, and the liquid metal is added to obtain the liquid metal emulsion.
[0032] In some embodiments of the present application, the prepared liquid metal emulsion, the solid-liquid ratio of the cellulose nanocrystal and water is 1g: (150-250) mL; the mass ratio of the liquid metal and the dispersion is 1: (10-20).
[0033] In some preferred embodiments of the present application, the prepared liquid metal emulsion, the solid-liquid ratio of the cellulose nanocrystal and water is 1g: (180-220) mL; the mass ratio of the liquid metal and the dispersion is 1: (10-15).
[0034] In some embodiments of the present application, the liquid metal comprises a gallium-based liquid metal.
[0035] In some embodiments of the present application, the gallium content of the gallium-based liquid metal is 70wt%-85wt%.
[0036] In some preferred embodiments of the present application, the gallium content of the gallium-based liquid metal is 75wt%-80wt%.
[0037] In some embodiments of the present application, the melting point of the gallium-based liquid metal is 16-30℃.
[0038] In some preferred embodiments of the present application, the gallium-based liquid metal comprises at least one of gallium-indium alloy, gallium-tin alloy, gallium-indium-tin alloy.
[0039] In some embodiments of the present application, the mixing of the cellulose nanocrystal and water is assisted by ultrasound.
[0040] In some embodiments of the present application, the power of the ultrasound is 150-350W, and the time is 5-10min.
[0041] In some preferred embodiments of the present application, the power of the ultrasound is 200-300W, and the time is 5-10min.
[0042] In some embodiments of the present application, the mixing of the liquid metal and the dispersion is assisted by ultrasound.
[0043] In some embodiments of the present application, the power of the ultrasound is 200-350W, and the time is 15-20min.
[0044] In some preferred embodiments of the present application, the power of the ultrasound is 240-300W, and the time is 15-20min.
[0045] In some embodiments of the present application, the mixing of the liquid metal and the dispersion is carried out in an ice bath.
[0046] In some embodiments of the present application, the liquid metal emulsion vacuum impregnation-freeze drying cycle is 3-4 times.
[0047] In some embodiments of the present application, the vacuum impregnation time is 10-20 min / time.
[0048] In some preferred embodiments of the present application, the vacuum impregnation time is 10-15 min / time.
[0049] In some embodiments of the present application, the vacuum impregnation is followed by a vacuum standing operation.
[0050] In some embodiments of the present application, the vacuum standing time is 10-15 h / time.
[0051] In some preferred embodiments of the present application, the vacuum standing time is 10-12 h / time.
[0052] In some embodiments of the present application, the freeze drying time is 30-40 h / time.
[0053] In some preferred embodiments of the present application, the freeze drying time is 35-40 h / time.
[0054] In some embodiments of the present application, the hot pressing pressure is 20-30 MPa, and the time is 2-5 h.
[0055] In some preferred embodiments of the present application, the hot pressing pressure is 20-25 MPa, and the time is 2-4 h.
[0056] In some embodiments of the present application, the hot pressing comprises using a flat plate vulcanizing instrument.
[0057] Specifically, the principle of the preparation method of the conductive / photothermal conversion material of the present application is explained as follows:
[0058] In the present application, porous wood is vacuum impregnated in a liquid metal emulsion. In the liquid metal emulsion, cellulose nanocrystals (CNC) act as an amphiphilic stabilizer, adsorbed on the surface of liquid metal microspheres, forming steric hindrance. The hydroxyl groups of CNC are affinity with wood cellulose, promoting the anchoring of the emulsion in the pore channel. Under vacuum conditions, the air in the pore channel is discharged by negative pressure, and the emulsion is pressed into the multi-stage pore channel by atmospheric pressure. Multiple cycles can ensure the filling rate of the liquid metal emulsion. After filling, the pore wall of the wood collapses under the pressure of hot pressing, and the liquid metal microspheres are broken and fused into a continuous liquid phase. The molten metal (melting point 16-30℃) flows under hot pressing, filling the nanoscale pores, and forming a three-dimensional conductive path.
[0059] The third aspect of the present application provides the application of the conductive / photothermal conversion material of the first aspect of the present application in the field of electronic device thermal management or building.
[0060] Compared with the prior art, the present application has the following beneficial effects:
[0061] The present application constructs a carrier material with hierarchical porous structure by selectively removing lignin and hemicellulose of wood while retaining the cellulose skeleton of wood, and the porosity is significantly improved, providing an ideal spatial structure for subsequent functionalization; using Pickering emulsion method stabilized by cellulose nanocrystals, a uniform dispersion of liquid metal with high surface tension is successfully prepared into a nano / micron-sized emulsion system, solving the compatibility problem of liquid metal with wood matrix; through vacuum impregnation combined with hot pressing process, uniform filling and continuous network construction of liquid metal emulsion in the porous structure of wood are realized, and the obtained composite material has excellent electrical conductivity and high-efficiency photothermal conversion performance, which can be applied in the field of electronic device thermal management as a high-efficiency thermal interface material or heating element, or applied in the field of building as a smart temperature regulating building material or energy-saving heating system, meeting market demand. BRIEF DESCRIPTION OF DRAWINGS
[0062] Figure 1 The physical pictures of the cellulose nanocrystal aqueous dispersion before (a) and after (b) mixing with the liquid metal emulsion in Example 1 and Comparative Example 1;
[0063] Figure 2 The physical pictures and SEM pictures of the original balsa wood, the delignified wood in Comparative Example 1 and the porous wood in Example 1;
[0064] Figure 3 The physical pictures and SEM pictures of the photothermal conversion material (a) in Comparative Example 1 and the conductive / photothermal conversion material (b) in Example 1;
[0065] Figure 4 The photothermal conversion diagram of the photothermal conversion material in Comparative Example 1;
[0066] Figure 5 The photothermal conversion diagram of the conductive / photothermal conversion material in Example 1;
[0067] Figure 6 The verification diagram of the electrical conductivity of the conductive / photothermal conversion material in Example 1;
[0068] Figure 7 The Joule heat test time-temperature curve of the conductive / photothermal conversion material in Example 1;
[0069] Figure 8 The Joule heat cycle stability test diagram of the conductive / photothermal conversion material in Example 1. DETAILED DESCRIPTION
[0070] The present application will be further described in details by specific examples. The raw materials, reagents or devices used in the examples and comparative examples are commercially available or can be obtained by prior art methods unless otherwise specified. The test or test method is the conventional method in the art unless otherwise specified.
[0071] Example 1
[0072] In this example, a conductive / photothermal conversion material is prepared by the following steps:
[0073] S1, cut the balsa wood into small pieces of 20mm x 20mm x 15mm, and use 5wt% NaOH solution to heat treat the wood pieces once, the treatment temperature is 80℃, the time is 6h, to remove the hemicellulose in the wood pieces, and then wash with distilled water; then use 2wt% NaClO2 solution to heat treat the wood pieces twice, and adjust the pH to 4-5 with glacial acetic acid, the treatment temperature is 80℃, the time is 24h, to remove the lignin in the wood pieces, and then wash with distilled water to obtain porous wood;
[0074] S2, mix 0.2g of cellulose nanocrystal powder with 39.8mL of deionized water, and ultrasonically disperse for 6min at 200W to obtain a cellulose nanocrystal aqueous dispersion; mix 2g of gallium-indium alloy liquid metal (gallium content is 75wt%, melting point is 20℃) with 18g of cellulose nanocrystal aqueous dispersion, and ultrasonically treat for 20min at 240W under ice water bath, then add 10g of cellulose nanocrystal aqueous dispersion and shake evenly to obtain a liquid metal emulsion;
[0075] S3, soak the porous wood in the liquid metal emulsion, vacuum soak for 10min, vacuum stand for 12h, and freeze-dry for 36h, repeat the above operation for 3 times, then use a flat plate vulcanizer to heat press the porous wood filled with the liquid metal emulsion, the heat pressing pressure is 25MPa, and the time is 3h to obtain the conductive / photothermal conversion material.
[0076] Comparative Example 1
[0077] In this comparative example, a photothermal conversion material is prepared by the following steps:
[0078] S1, cut the balsa wood into small pieces of 20mm x 20mm x 15mm, and use 5wt% NaOH solution to heat treat the wood pieces once, the treatment temperature is 80℃, the time is 6h, to remove the hemicellulose in the wood pieces, and then wash with distilled water; then use 2wt% NaClO2 solution to heat treat the wood pieces twice, and adjust the pH to 4-5 with glacial acetic acid, the treatment temperature is 80℃, the time is 24h, to remove the lignin in the wood pieces, and then wash with distilled water to obtain porous wood;
[0079] S2, 0.2 g of cellulose nanocrystal powder was mixed with 39.8 mL of deionized water, and ultrasonic dispersion was performed at 200 W for 6 min to obtain a cellulose nanocrystal aqueous dispersion; 2 g of gallium-indium alloy liquid metal (gallium content of 75 wt%, melting point of 20°C) was mixed with 18 g of the cellulose nanocrystal aqueous dispersion, and ultrasonic treatment was performed at 240 W for 20 min under the condition of an ice water bath, and then 10 g of the cellulose nanocrystal aqueous dispersion was added and shaken uniformly to obtain a liquid metal emulsion;
[0080] S3, the delignified wood was immersed in the liquid metal emulsion, vacuum impregnated for 10 min, vacuum standing for 12 h, and freeze-dried for 36 h, and the above operation was repeated for 3 times to obtain a light-heat conversion material.
[0081] Figure 1 For the actual photos of the cellulose nanocrystal aqueous dispersion before mixing with the liquid metal emulsion (a) and after mixing (b) in Example 1 and Comparative Example 1, Figure 1 (a) in which the cellulose nanocrystal aqueous dispersion (transparent) and the gallium-indium alloy liquid metal (silver gray metal droplets) are in a physical mixing state, Figure 1 (b) in which the cellulose nanocrystal aqueous dispersion and the gallium-indium alloy liquid metal form a liquid metal emulsion by ultrasonic emulsification, which appears as a uniform gray-black suspension.
[0082] Figure 2 For the actual photos and SEM images of the original balsa wood, the delignified wood in Comparative Example 1 and the porous wood in Example 1, wherein, Figure 2 (a) in which the actual photo (left) and SEM image (right) of the original balsa wood, Figure 2 (b) in which the actual photo (left) and SEM image (right) of the delignified wood in Comparative Example 1, Figure 2 (c) in which the actual photo (left) and SEM image (right) of the porous wood in Example 1. It can be seen from Figure 2 that the original balsa wood has a dense cell wall structure, and the pores are filled with lignin / hemicellulose; after removing the lignin, part of the pores are opened, but there is still hemicellulose remaining; after removing the hemicellulose and lignin, the porous wood obtained presents a completely open honeycomb-like porous structure, and the cell wall is thin, indicating that the chemical treatment significantly improves the porosity of the wood, providing space for the filling of the liquid metal emulsion, and the through-pore structure of the porous wood becomes the basis for efficient impregnation of the liquid metal emulsion.
[0083] Figure 3 For the actual photos and SEM images of the light-heat conversion material (a) in Comparative Example 1 and the conductive / light-heat conversion material (b) in Example 1, wherein, Figure 3 (a) in which the actual photo (left) and SEM image (right) of the light-heat conversion material in Comparative Example 1, Figure 3Image (b) shows a physical photograph (left) and a SEM image (right) of the conductive / photothermal conversion material in Example 1. Figure 3 As can be seen, the material in Comparative Example 1, after being impregnated with liquid metal emulsion, appears gray. SEM shows that spherical liquid metal microspheres are attached to the pores. The uniform dispersion of the microspheres preserves the photothermal conversion capability. The material in Example 1, after being impregnated with liquid metal emulsion and hot-pressed, exhibits a metallic luster. SEM shows that the pores inside the material collapse, and the liquid metal forms a continuous thin film. The continuous metal phase forms a conductive path, enabling the material to have both electrical conductivity and photothermal conversion capability.
[0084] Figure 4 To illustrate the photothermal conversion of the photothermal conversion material in Comparative Example 1, the material was fixed 40 cm away from a near-infrared light source. Under different near-infrared light powers (power gradient 0.1-0.4 W), the surface temperature data of the material was recorded by an infrared thermal imager during a 60-second temperature increase and a 30-second temperature decrease. The data was then exported and plotted. Figure 4 It can be seen that during the 60s heating process, the surface temperature of the photothermal conversion material in Comparative Example 1 showed a rapid increase followed by a gradual decrease. Within the 30s cooling range, the surface temperature of the material also showed a rapid decrease. Moreover, at the same heating time point, the surface temperature of the material increased with the increase of near-infrared light power, indicating that the filling of liquid metal emulsion enabled the wood to obtain excellent photothermal conversion capability.
[0085] Figure 5 The image shows the photothermal conversion of the conductive / photothermal conversion material in Example 1. The material was fixed 40 cm from a near-infrared light source. Under different near-infrared light powers (power gradient 0.1-0.4 W), the surface temperature of the material was recorded by an infrared thermal imager within a 60-second temperature increase and a 30-second temperature decrease range. The data was then exported and plotted. Figure 5 It can be seen that during the 60s heating process, the surface temperature of the conductive / photothermal conversion material in Example 1 gradually increased, and within the 30s cooling range, the surface temperature of the material also gradually decreased. At the same heating time point, the surface temperature of the material increased with the increase of near-infrared light power, indicating that the material obtained in Example 1 has photothermal conversion capability. Compared with the material in Comparative Example 1, under the same power conditions, the temperature rise rate and the maximum temperature that can be reached on the material surface both decreased, indicating that hot pressing caused the microspheres to break, and the continuous metallic phase reduced the light absorption efficiency.
[0086] Figure 6 This is a diagram verifying the conductivity of the conductive / photothermal conversion material in Example 1. Figure 6It can be seen that by replacing part of the wires with the conductive / photothermal conversion material in Example 1 and connecting them in the circuit, the light bulb was successfully lit. This indicates that hot pressing causes the liquid metal to form a continuous thin film, and the continuous metal phase forms a conductive network, giving the material in Example 1 conductivity.
[0087] Figure 7 The Joule thermal test time-temperature curve of the conductive / photothermal conversion material in Example 1 is shown. A 5mm wide conductive / photothermal conversion material was connected in a circuit, and the surface temperature data of the material was recorded by an infrared thermal imager within a range of 60s of power-on and 30s of power-off under different current magnitudes (0.3-0.9A). The data was then exported and plotted. Figure 7 It can be seen that under a certain current, the material heats up rapidly within 60 seconds, and the temperature drops back to the initial temperature within 30 seconds after the power is turned off. Moreover, the temperature change is positively correlated with the current magnitude. The linear increase of temperature with current confirms that the liquid metal forms a low-resistance continuous phase in the wood, providing an efficient pathway for electron transport. The rapid heating / cooling response indicates that the material has excellent thermal conductivity and heat dissipation efficiency, making it suitable for electronic devices that require rapid thermal regulation. The temperature gradient under different currents is controllable, indicating that the material has reliability and repeatability in thermal management applications.
[0088] Figure 8 This is a Joule thermal cycling stability test diagram of the conductive / photothermal conversion material in Example 1. A 5mm wide strip of the conductive / photothermal conversion material was connected in a circuit. Under a 0.5A current, the surface temperature data of the material was recorded by an infrared thermal imager during 10 cycles from the highest to the lowest temperature. The data was then exported and plotted. Figure 8 It can be seen that after 10 consecutive heating (power-on) and cooling (power-off) cycles, the highest temperature in each cycle stabilized at about 80℃, and the lowest temperature returned to the initial temperature. The temperature fluctuation range was less than 5%, and there was no significant performance degradation. This indicates that the liquid metal network has excellent mechanical and thermal stability in the wood pores, avoiding structural damage or metal oxidation failure under repeated thermal stress. The stable Joule thermal properties verify the reliability of the material in long-term use (such as thermal management of electronic devices) and can meet the cycle life requirements of industrial scenarios. The small temperature fluctuation (<5%) indirectly proves the tight bonding between the liquid metal and the wood cellulose skeleton, indicating that the hot pressing process effectively inhibits the migration or peeling of the metal phase during the cycle.
Claims
1. An electro-conductive / photothermal conversion material, characterized by, The porous wood is filled with liquid metal in a continuous liquid phase.
2. The electro-conductive / photothermal conversion material according to claim 1, wherein, The porous wood is obtained by removing lignin and hemicellulose from wood.
3. The electro-conductive / photothermal conversion material according to claim 2, wherein, The porous wood is obtained by a method comprising the following steps: 1) removing hemicellulose by first treating wood with an alkali hydroxide solution; 2) removing lignin by second treating wood with an oxidant.
4. The electro-conductive / photothermal conversion material according to claim 3, wherein The concentration of the alkali hydroxide solution is 3wt%-7wt% and the first treating temperature is 64-96℃ for 4-10h.
5. The electrically conductive / photothermal conversion material according to claim 3, wherein The concentration of the oxidant is 1wt%-3wt% and the second treating pH is 4-5, temperature is 64-96℃ for 24-48h.
6. The method of producing the electro-conductive / photothermal conversion material according to any one of claims 1 to 5, characterized by, The method comprises the following steps: The porous wood is vacuum impregnated with liquid metal emulsion, freeze-dried, and hot-pressed to obtain the conductive / photothermal conversion material.
7. The production method according to claim 6, wherein The liquid metal emulsion is obtained by a method comprising the following steps: The cellulose nanocrystal is mixed with water to form a dispersion, and then liquid metal is added to obtain the liquid metal emulsion.
8. The preparation method according to claim 7, characterized in that, The solid-liquid ratio of the cellulose nanocrystal to water is 1g: (150-250)mL and the mass ratio of the liquid metal to the dispersion is 1: (10-20).
9. The preparation method according to claim 6, characterized in that, The vacuum impregnation time is 10-20min / time. The hot-pressing pressure is 20-30MPa for 2-5h.
10. The conductive / photothermal conversion material of any one of claims 1-5 for use in the field of electronic device thermal management or building.