Composite carbon aerogel film porous material and preparation method and application thereof
By mixing a Pickering emulsion co-stabilized with nanocellulose and graphene oxide with paraffin, and combining it with filtration, freeze-drying and annealing, the problems of complex and costly preparation of traditional carbon aerogel films are solved. This enables the simple preparation of lightweight, flexible, highly conductive and thermally conductive carbon aerogel films with excellent photothermal conversion and piezoresistive sensing performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUILIN UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2023-04-20
- Publication Date
- 2026-06-30
AI Technical Summary
Traditional methods for preparing carbon aerogel films are complex and costly, making it difficult to easily obtain lightweight, flexible, highly conductive and thermally conductive carbon aerogel films.
Composite carbon aerogel films were prepared by mixing a Pickering emulsion co-stabilized with nanocellulose and graphene oxide with paraffin, followed by filtration, freeze-drying, and annealing. The specific steps included mixing, ultrasonic treatment, filtration, freeze-drying, and three-stage annealing.
The preparation process is simple and low-cost, and the resulting composite carbon aerogel film has excellent photothermal conversion, Joule heating properties and piezoresistive sensing properties, making it suitable for flexible sensors and wearable devices.
Smart Images
Figure CN116812903B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of porous material preparation technology, and in particular to a composite carbon aerogel thin film porous material, its preparation method and application. Background Technology
[0002] With the rapid development of the Internet of Things (IoT), wearable smart devices are highly anticipated in the field of personalized medicine. For example, wearable electronic sensors can be used for fitness tracking, personal health monitoring, and diagnosis; wearable thermotherapy devices can be used to treat joint pain, swelling, and repair muscle fibers. Therefore, wearable devices are also considered the next frontier in personalized medicine, as they are playing an evolving role from monitoring fitness to improving diagnosis and healthcare. The mainstream materials used in the manufacture of wearable devices are primarily metals, carbon-based materials, and polymers. Among these, carbon-based materials are widely used as functional materials for wearable devices due to their good electrical conductivity, chemical stability, and ease of functionalization.
[0003] Carbon aerogels, as carbon-based materials, have attracted widespread attention from researchers in recent years due to their remarkable properties (lightweight, porous, and high specific surface area). The earliest carbon aerogels were prepared using resorcinol-formaldehyde as a precursor via a sol-gel process and high-temperature carbonization (inert atmosphere). To date, a series of carbon-based aerogels with high electrical / thermal conductivity, such as carbon nanotube (CNT) sponges, carbon nanofiber (CNF) aerogels, graphene or graphene oxide (GO) aerogels, and CNT / graphene hybrid aerogels, have been developed and applied. Among these, GO is an ideal precursor for constructing carbon aerogels because of its unique two-dimensional morphology, ease of assembly, flexibility, and good mechanical strength.
[0004] However, with the diversification of application requirements and the increasing complexity of application scenarios, carbon aerogels, in addition to their bulk form, need to be designed into various shapes, especially self-supporting carbon aerogel films. Traditional methods for preparing carbon aerogel films often employ blade coating technology, rolling processes, or template molding, which typically lead to complex preparation steps and high costs. Therefore, developing a simple and low-cost method to prepare lightweight, flexible carbon aerogel films with high electrical and thermal conductivity is a critical issue that urgently needs to be addressed. Summary of the Invention
[0005] The purpose of this invention is to provide a composite carbon aerogel thin film porous material, its preparation method and application, to solve the problems existing in the prior art, thereby obtaining a composite carbon aerogel thin film porous material with excellent performance using a simple preparation method.
[0006] To achieve the above objectives, the present invention provides the following solution:
[0007] This invention provides a method for preparing a composite carbon aerogel membrane porous material: a Pickering emulsion is obtained by co-stabilizing an organic solution containing paraffin with nanocellulose and graphene oxide, the Pickering emulsion is filtered, the resulting filter cake is freeze-dried and annealed to obtain the composite carbon aerogel membrane porous material.
[0008] Furthermore, the preparation method includes the following steps:
[0009] A mixed aqueous dispersion of nanocellulose-graphene oxide was mixed with an organic solution containing paraffin, and the resulting mixture was subjected to ultrasonic treatment to obtain a water-in-oil Pickering emulsion with nanocellulose stability.
[0010] The Pickering emulsion was filtered to obtain a nanocellulose-graphene oxide / paraffin composite filter cake.
[0011] The nanocellulose-graphene oxide / paraffin composite filter cake was freeze-dried to obtain nanocellulose-graphene oxide / paraffin composite aerogel.
[0012] The nanocellulose-graphene oxide / paraffin composite aerogel was annealed to obtain the composite carbon aerogel thin film porous material.
[0013] Furthermore, in the organic solution containing paraffin, the concentration of paraffin is 1-99 wt%; in the nanocellulose-graphene oxide mixed aqueous dispersion, the total concentration of nanocellulose and graphene oxide is 0.4-2.0 wt%, wherein the concentration ratio of nanocellulose to graphene oxide is 1:1.
[0014] Furthermore, the volume ratio of the nanocellulose-graphene oxide mixed aqueous dispersion to the paraffin organic solution is 1:1-10:1.
[0015] Furthermore, in the paraffin-containing organic solution, the organic solvent is an organic solvent that is immiscible with water and can dissolve paraffin. Examples include dichloromethane, 1,2-dichloroethane, chloroform, n-hexane, and cyclohexane.
[0016] In this invention, the microstructure of the composite carbon aerogel film material can be controlled by adjusting the paraffin concentration.
[0017] The freeze-drying process is preferably carried out by freezing at -30 to -10°C for 8 hours, followed by freezing at -50°C and a vacuum of 25 Pa for 48 hours.
[0018] Furthermore, the annealing process adopts a three-stage annealing process: in the first stage, the temperature is raised from 25°C to 200°C and held at 200°C for 30 minutes; in the second stage, the temperature is raised from 200°C to 400°C and held at 400°C for 20 minutes; in the third stage, the temperature is raised from 400°C to 800°C and held at 800°C for 90 minutes.
[0019] Furthermore, the heating rate in the first stage is 5℃ / min, the heating rate in the second stage is 1℃ / min, and the heating rate in the third stage is 5℃ / min.
[0020] The second technical solution of the present invention provides a composite carbon aerogel thin film porous material prepared by the above preparation method.
[0021] The third technical solution of this invention provides the application of the above-mentioned composite carbon aerogel thin film porous material in the fields of photothermal conversion and piezoresistive sensing.
[0022] The composite carbon aerogel thin film porous material of the present invention has photothermal, electrothermal and biosensing properties, making it particularly suitable for use in flexible sensors. Moreover, the preparation method is simple, realizing the convenient preparation of composite carbon aerogel thin film materials.
[0023] In this invention, the nanocellulose is a cellulose material with at least one nanometer scale, including cellulose nanocrystals and cellulose nanofibers with different aspect ratios extracted and prepared from various plant raw materials, including cotton, wood, bamboo and hemp.
[0024] In this invention, the purity of the chemical reagents and raw materials is analytical grade or higher.
[0025] The present invention discloses the following technical effects:
[0026] (1) The method of the present invention is applicable to various nanocellulose stable organic solutions containing paraffin and incompatible with water, and has universal applicability.
[0027] (2) The process of the method of the present invention is simple, fast and low cost.
[0028] (3) The preparation process of this invention is simple and highly scalable. The resulting composite carbon aerogel film porous material has excellent photothermal conversion performance, Joule thermal performance and piezoresistive sensing performance, and has good application prospects in the fields of photothermal conversion, personal thermal management and flexible sensors. Attached Figure Description
[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0030] Figure 1 SEM images of the composite aerogel film and composite carbon aerogel film porous materials prepared in Examples 1-3 of the present invention; wherein, (a)-(c) are SEM images of the composite aerogel film prepared in Examples 1-3, and (d)-(f) are SEM images of the composite carbon aerogel film porous materials prepared in Examples 1-3, respectively.
[0031] Figure 2 In the image, (a) is an infrared thermal image of the composite carbon aerogel film porous material obtained in Example 2 under different light intensities, and (b) is a time-temperature curve of the composite carbon aerogel film porous material obtained in Example 2.
[0032] Figure 3 In the figure, (a) is the time-temperature curve of the composite carbon aerogel film porous material obtained in Example 2 under different voltages, and (b) is the fitting curve of the square of the working voltage and the saturation temperature of the composite carbon aerogel film porous material obtained in Example 2.
[0033] Figure 4 In the diagram, (a) shows the current response of the composite carbon aerogel film porous material obtained in Example 2 under regular pressure. Figure 4 (b) is a graph showing the composite carbon aerogel film porous material obtained in Example 2 applied to a wearable sensor to monitor the current signal of the human carotid artery. Detailed Implementation
[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0035] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0036] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0037] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.
[0038] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0039] This invention utilizes nanocellulose and graphene oxide to co-stabilize 1,2-dichloroethane droplets containing paraffin wax, followed by ultrasonic emulsification to form a stable Pickering emulsion. This emulsion is then combined with vacuum filtration and freeze-drying techniques to obtain a nanocellulose-graphene oxide / paraffin wax composite aerogel film. Finally, a high-temperature annealing process is used to obtain a nanocellulose-reduced graphene oxide / paraffin wax composite carbon aerogel film material, which is a composite carbon aerogel film material that combines photothermal, electrothermal, and biosensing functions.
[0040] Example 1: Preparation of composite carbon aerogel thin film porous material
[0041] (1) Take 1.0 mL of 10 wt% paraffin in 1,2-dichloroethane solution and add it to 5.0 mL of 0.4% aqueous dispersion of nanocellulose-graphene oxide mixture (wherein, the mass concentration of nanocellulose and graphene oxide aqueous dispersion is 0.2 wt%). Then, sonicate the mixture in an ultrasonic instrument with a power of 400 W at 60 °C for 5 min, shake by hand, and repeat 6 times to obtain a nanocellulose-stable oil-in-water Pickering emulsion.
[0042] (2) Pour the Pickering emulsion obtained in step (1) into a mobile phase filter and seal it with plastic wrap. Then, after vacuum filtration for 21 hours, nanocellulose-graphene oxide / paraffin composite filter cake is obtained.
[0043] (3) The nanocellulose-graphene oxide / paraffin composite filter cake obtained in step (2) is frozen at -30 to -10℃ for 8 hours, and then placed in a freeze dryer at -50℃ and a vacuum degree of 25Pa for 48 hours to obtain a composite aerogel film (nanocellulose-graphene oxide / paraffin composite aerogel film) with a thickness of 0.89mm.
[0044] (4) The nanocellulose-graphene oxide / paraffin composite aerogel film obtained in step (3) is subjected to thermal annealing. The thermal annealing process is as follows: the temperature is raised from 25℃ to 200℃ at a rate of 5℃ / min, and held at 200℃ for 30min. Then the temperature is raised from 200℃ to 400℃ at a rate of 1℃ / min, and held at 400℃ for 20min. Finally, the temperature is raised from 400℃ to 800℃ at a rate of 5℃ / min, and held at 800℃ for 90min. A composite carbon aerogel film porous material with a thickness of 0.73mm (nanocellulose-reduced graphene oxide / paraffin composite carbon aerogel film porous material) can be obtained.
[0045] Example 2: Preparation of porous composite carbon aerogel film materials
[0046] (1) Take 1.0 mL of 1,2-dichloroethane solution of paraffin with a mass concentration of 30 wt%; add it to 5.0 mL of aqueous dispersion of nanocellulose-graphene oxide with a mass concentration of 0.4% (wherein, the mass concentration of nanocellulose and graphene oxide aqueous dispersion is 0.2 wt%), and then sonicate the mixture in an ultrasonic instrument with a power of 400 W at 60 °C for 5 min, shake by hand, and repeat 6 times to obtain a water-in-oil Pickering emulsion of nanocellulose.
[0047] (2) Pour the Pickering emulsion obtained in step (1) into a mobile phase filter and seal it with plastic wrap. Then, after vacuum filtration for 21 hours, nanocellulose-graphene oxide / paraffin composite filter cake is obtained.
[0048] (3) The nanocellulose-graphene oxide / paraffin composite filter cake obtained in step (2) is frozen at -30 to -10℃ for 8 hours, and then placed in a freeze dryer at -50℃ and a vacuum degree of 25Pa for 48 hours to obtain a nanocellulose-graphene oxide / paraffin composite aerogel film with a thickness of 1.43mm.
[0049] (4) The nanocellulose-reduced graphene oxide / paraffin composite aerogel film obtained in step (3) is subjected to thermal annealing. The thermal annealing process is as follows: the temperature is raised from 25°C to 200°C at a rate of 5°C / min, and held at 200°C for 30 min. Then the temperature is raised from 200°C to 400°C at a rate of 1°C / min, and held at 400°C for 20 min. Finally, the temperature is raised from 400°C to 800°C at a rate of 5°C / min, and held at 800°C for 90 min. A porous nanocellulose-reduced graphene oxide / paraffin composite carbon aerogel film with a thickness of 1.26 mm can be obtained.
[0050] Example 3: Preparation of composite carbon aerogel thin film porous material
[0051] (1) Take 1.0 mL of 1,2-dichloroethane solution of paraffin with a mass concentration of 50 wt%; add it to 5.0 mL of aqueous dispersion of nanocellulose-graphene oxide with a mass concentration of 0.4% (wherein, the mass concentration of nanocellulose and graphene oxide aqueous dispersion is 0.2 wt%), and then sonicate the mixture in an ultrasonic instrument with a power of 400 W at 60 °C for 5 min, shake by hand, and repeat 6 times to obtain a water-in-oil Pickering emulsion of nanocellulose.
[0052] (2) Pour the Pickering emulsion obtained in step (1) into a mobile phase filter and seal it with plastic wrap. Then, after vacuum filtration for 21 hours, nanocellulose-graphene oxide / paraffin composite filter cake is obtained.
[0053] (3) The nanocellulose-graphene oxide / paraffin composite filter cake obtained in step (2) is frozen at -30 to -10℃ for 8 hours, and then placed in a freeze dryer at -50℃ and a vacuum degree of 25Pa for 48 hours to obtain a nanocellulose-graphene oxide / paraffin composite aerogel film with a thickness of 2.11mm.
[0054] (4) The nanocellulose-reduced graphene oxide / paraffin composite aerogel film obtained in step (3) is subjected to thermal annealing. The thermal annealing process is as follows: the temperature is raised from 25℃ to 200℃ at a rate of 5℃ / min, and held at 200℃ for 30min. Then the temperature is raised from 200℃ to 400℃ at a rate of 1℃ / min, and held at 400℃ for 20min. Finally, the temperature is raised from 400℃ to 800℃ at a rate of 5℃ / min, and held at 800℃ for 90min. A porous nanocellulose-reduced graphene oxide / paraffin composite carbon aerogel film with a thickness of 2.07mm can be obtained.
[0055] The composite aerogel film and composite carbon aerogel film porous materials prepared by the Zeiss field emission scanning electron microscope are shown in the figure. Figure 1 .in, Figure 1 (a)-(c) are SEM images of the composite aerogel films prepared in Examples 1-3, respectively; Figure 1 (d)-(f) are SEM images of the composite carbon aerogel film porous materials prepared in Examples 1-3, respectively.
[0056] from Figure 1 As can be seen, in the three composite aerogel films, paraffin is encapsulated by nanocellulose and graphene oxide. In the three composite carbon aerogel film porous materials obtained after carbonization, the paraffin is pyrolyzed, leaving pores and ultimately forming a porous structure. Among them, the composite carbon aerogel film porous material obtained in Example 2 has a more regular pore structure and a more complete cross-linking structure between pore walls.
[0057] A CEL-S500 xenon lamp was used to simulate sunlight, and a Fluke Ti32 infrared camera was used to test the photothermal conversion performance. Figure 2 (a) shows the composite carbon aerogel film porous material obtained in Example 2 under different light intensities (50mW / cm²). 2 -200mW / cm 2 The infrared thermal image shows that the saturation temperature of the composite carbon aerogel film porous material increases with the increase of light intensity.
[0058] Figure 2 (b) is the time-temperature curve of the composite carbon aerogel film porous material obtained in Example 2, under different light intensities (50mW / cm²). 2 -200 mW / cm 2 Under normal solar radiation (100 mW / cm²), the composite carbon aerogel porous materials all exhibited rapid initial heating followed by isothermal behavior after reaching saturation temperature. 2 Its saturation temperature under irradiation can reach 71.4℃, and its excellent performance makes it a promising candidate for application in the field of photothermal conversion.
[0059] The electrothermal properties of the composite carbon aerogel thin film porous material were tested using a JJW3-1000VA AC regulated power supply. Figure 3 (a) shows the time-temperature curves of the composite carbon aerogel film porous material obtained in Example 2 under different voltages (1V-5V). As the working voltage gradually increases, the saturation temperature of the composite carbon aerogel film porous material also increases. Figure 3(b) is the fitting curve of the square of the working voltage and the saturation temperature of the composite carbon aerogel film porous material obtained in Example 2. The saturation temperature of the composite carbon aerogel film porous material has a good linear relationship with the square of the working voltage. Therefore, the saturation temperature of the composite carbon aerogel film porous material can be easily adjusted by adjusting the applied voltage, and it has great potential as an electric heater device for personal thermal management.
[0060] The piezoresistive sensing performance of composite carbon aerogel thin film porous materials was tested using a CHI690 electrochemical workstation. Figure 4 (a) is the current response diagram of the composite carbon aerogel film porous material obtained in Example 2 under regular pressure. Figure 4 (b) is a graph showing the composite carbon aerogel film porous material obtained in Example 2 applied to a wearable sensor to monitor the current signal of the human carotid artery. Figure 4 As shown in (a), the response current increases with increasing stress. This is because pressure compression causes the RGO sheets that make up the pore walls of the composite carbon aerogel film to come into contact with each other, increasing the conductive pathways and thus reducing resistance. Furthermore, sensitivity (S) is a key indicator for evaluating the sensing performance of piezoresistive sensors, defined as the ratio of the relative change in current to the change in applied pressure. According to the calculation formula... Its sensitivity (S) can be calculated to be 0.12 kPa. -1 Furthermore, it can be applied to wearable sensors, such as... Figure 4 (b) A sensor based on a composite carbon aerogel thin film porous material can accurately detect a volunteer's carotid pulse at 69 beats / minute (the pulse rate of a healthy adult is 60-100 beats / minute) and accurately identify the two characteristic peaks of a single carotid pulse signal, namely the shock wave (P) and the diastolic wave (D). Therefore, it has good application prospects in the field of wearable flexible sensors.
[0061] Comparative Example 1
[0062] The only difference from Example 2 is that the three-stage heating is not used. The specific heating steps are as follows: the temperature is directly increased from 25°C to 800°C at a heating rate of 5°C / min, and then held at that temperature for 90min to obtain a composite carbon aerogel film.
[0063] Results: The carbon aerogel film prepared by directly heating from 25℃ to 800℃ experienced significant volume and thickness shrinkage. In contrast, the composite carbon aerogel film prepared by the three-stage heating method exhibited less volume and thickness shrinkage. This is because the three-stage heating was designed based on the thermal properties of the composite carbon aerogel film. The 200-400℃ range corresponds to the thermal degradation process of CNF, GO, and PW. During this stage, the weight loss of the composite carbon aerogel film is substantial. Therefore, using a lower heating rate effectively avoids the rapid pyrolysis of CNF, GO, and PW, thereby increasing the residual carbon content and effectively reducing shrinkage.
[0064] Comparative Example 2
[0065] A carbon aerogel film was prepared using existing technology, with the following specific steps: An aramid nanofiber (ANF) suspension was coated onto a 2 mm thick glass surface. The resulting coating was then immersed in deionized water for solvent exchange for 3 days to complete gelation. Subsequently, it was peeled off from the glass surface to obtain an aramid nanofiber (ANF) hydrogel film. The hydrogel film was freeze-dried for 72 hours to transform into an aerogel film, which was then subjected to a specific two-stage carbonization process under an argon atmosphere to obtain an ANF-derived carbon aerogel film. The specific carbonization process was as follows: the temperature was increased from room temperature to 500℃ at a heating rate of 2℃ / min and held for 2 hours, followed by a further increase to 1500℃ at a rate of 5℃ / min and held for 2 hours.
[0066] Results: The ANF-derived carbon aerogel film exhibits photothermal conversion capability due to its rough surface and the inherent light absorption of black carbon materials, achieving a value of 200 mW / cm². 2 The saturation temperature that can be reached under light intensity is approximately 95℃.
[0067] The composite carbon aerogel film prepared by the method of this invention, under the same light intensity (200 mW / cm), 2 The achievable saturation temperature is 115.3℃. In comparison, the preparation method proposed in this invention is not only simple and easy to implement, but also quick, and the photothermal conversion performance of the prepared composite carbon aerogel film is also superior.
[0068] The composite carbon aerogel film material with a special porous structure prepared by the method of the present invention has excellent photothermal conversion performance, Joule thermal performance and piezoresistive sensing performance, showing great application potential in the field of wearable thermal managers, and can also meet the practical application requirements in the field of flexible sensors.
[0069] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A method for preparing a composite carbon aerogel thin film porous material, characterized in that, Includes the following steps: A mixed aqueous dispersion of nanocellulose-graphene oxide was mixed with an organic solution containing paraffin, and the resulting mixture was ultrasonically treated to obtain a Pickering emulsion. The Pickering emulsion was filtered to obtain a nanocellulose-graphene oxide / paraffin composite filter cake. The nanocellulose-graphene oxide / paraffin composite filter cake was freeze-dried to obtain nanocellulose-graphene oxide / paraffin composite aerogel. The nanocellulose-graphene oxide / paraffin composite aerogel was annealed to obtain the composite carbon aerogel thin film porous material. The annealing process adopts a three-stage annealing process: the first stage involves heating from 25°C to 200°C and holding at 200°C for 30 minutes. The second stage involves raising the temperature from 200℃ to 400℃ and holding it at 400℃ for 20 minutes. The third stage involves raising the temperature from 400℃ to 800℃ and holding it at 800℃ for 90 minutes. The heating rate for the first stage is 5℃ / min, the heating rate for the second stage is 1℃ / min, and the heating rate for the third stage is 5℃ / min. The concentration of paraffin in the organic solution is 10-50 wt%; the total concentration of nanocellulose and graphene oxide in the mixed aqueous dispersion is 0.4-2.0 wt%, wherein the concentration ratio of nanocellulose to graphene oxide is 1:
1. The volume ratio of the nanocellulose-graphene oxide mixed aqueous dispersion to the paraffin-containing organic solution is 1:1-10:
1. In the organic solution containing paraffin, the organic solvent in the organic solution is an organic solvent that is incompatible with water and can dissolve paraffin.
2. A composite carbon aerogel thin film porous material prepared by the preparation method described in claim 1.
3. The application of the composite carbon aerogel thin film porous material as described in claim 2 in the fields of photothermal conversion and piezoresistive sensing.