A carboxymethyl chitosan-based nanoporous aerogel and a preparation method and application thereof

Abstract

This invention discloses a nanoporous aerogel based on carboxymethyl chitosan, its preparation method, and its application, belonging to the field of biomass-based aerogel technology. By weight, the raw materials for preparing the aerogel include 2.5 parts deionized water, 0.075 parts carboxymethyl chitosan (CMC), 0.0075-0.0225 parts carboxylated multi-walled carbon nanotubes (C-CNT), 0.01125 parts glutaraldehyde (GA), 0.01 parts poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT:PSS), and 10 parts dimethyl sulfoxide (DMSO). This invention uses CMC as the matrix and C-CNT as the internal conductive and strength-enhancing material to form a hydrogel under the action of crosslinking agent GA. CMC / C-CNT aerogel is then prepared by directional freeze-drying. PEDOT:PSS is then dip-coated to obtain CMC / C-CNT / PEDOT:PSS as the external conductive material, which forms a double conductive network with the internal C-CNT, thus preparing an aerogel with excellent conductivity and mechanical properties. The prepared aerogel is used to prepare an aerogel sensor, which has high mechanical and electrical properties.

Description

Technical Field

[0001] This invention relates to the field of biomass-based aerogel technology, and in particular to a nanoporous aerogel based on carboxymethyl chitosan, its preparation method, and its application. Background Technology

[0002] Aerogels are nanoporous materials with excellent physicochemical properties, including high porosity, low density, high specific surface area, and adjustable surface chemical energy. They possess superior properties in thermal, acoustic, mechanical, and optical aspects, leading to extensive research in areas such as temperature resistance, electromagnetic shielding, sensing, adsorption, energy storage, and catalysis. Among these, the application of highly flexible, high-specific-surface-area, and highly conductive aerogel materials in flexible pressure sensors has attracted widespread attention. Current research largely uses polymers such as polydimethylsiloxane, polyurethane, polystyrene, and polyimide as matrices, and carbon-based materials, metal nanomaterials, and conductive polymers as conductive materials, forming polymeric composite materials with good conductivity and flexibility. In recent years, constructing flexible conductive aerogel materials with a three-dimensional network structure has become a more popular strategy. This approach utilizes the nanoporous structure of aerogels while introducing excellent conductivity, avoiding the poor mechanical properties of inorganic aerogels. Furthermore, aerogels are highly porous, lightweight, and unique solid structures composed of a three-dimensional interconnected network filled with numerous air pores. These air-filled pores enhance the physicochemical properties and structural features of aerogels on a macroscopic scale and integrate the typical characteristics of aerogels.

[0003] Silica aerogel is one of the earliest types of aerogels and belongs to the category of inorganic aerogels. The precursors used for synthesizing silica aerogels are mainly water glass and various silanes, such as tetramethyloxysilane, tetraethoxysilane, and polyoxydisiloxane. Natural silica aerogels are hygroscopic, and the residual Si-OH bonds on the silica surface are the cause of this hygroscopicity. To address this issue, surface modification is needed to improve the stability of the aerogel. Silanes containing hydrophobic organic groups are typically used to impart hydrophobic properties to the aerogel. Bhagat et al. used a co-precursor method to modify the surface of hydrogels to obtain aerogel beads. They proposed a simple and economical method to obtain silica aerogels by surface modification of hydrogels with extremely low concentrations of hexamethyldisilazane (HMDZ) (Bhagat SD, Kim YH, Moon MJ, et al. A cost-effective and fast synthesis of nanoporous SiO2 aerogel powders using water-glass via ambient pressure drying route[J]. Solid State Science. 2007, 9: 628-635.). First, the water glass was treated with a mixture of HNO3 / HMDZ, and HNO3 promoted the hydrolysis of HMDZ. Surface modification and solvent exchange occurred simultaneously, resulting in superhydrophobic aerogels. Cok et al. used different silicides for two-step surface modification to prepare tetraethoxysilane-derived silica aerogels ( SS, Gizli N. Hydrophobic silica aerogels synthesized inambient conditions by preserving the porous structure via two-step silylation[J].Ceramics International,2020,46,27789-27799.), to obtain aerogels with high specific surface area and high hydrophobicity. Although silica aerogels have excellent properties and potential applications, most conventional silica aerogels have low mechanical strength, and their hydrophilicity makes them unstable under atmospheric conditions. Metal aerogels have attracted widespread attention due to their high surface area and ultra-low density. Qian et al. reported the synthesis of ultralight gold aerogel monomers with tunable pore density and structure. Different solvents and their suspensions are key parameters for systemically adjusting the overall density and pore structure of gold aerogels (Qian, F, Troksa A, Fears TM, et al. Gold aerogel monoliths with tunable ultralow densities[J]. Nano Letters, 2019, 20: 131-135.). Yan et al. reported a 3D printing technique and cryogenic casting method for the fabrication of metal aerogels. The results showed that the density is controllable and high conductivity can be achieved by using these techniques (Yan P, Brown E, Su Q, Li J, et al. 3D printing hierarchical silver nanowire aerogel with highly compressive resilience and tensile elo ngation through tunable poisson's ratio[J]. Small, 2017, 13: 170-1756.). However, the complexity and high cost of many metal aerogel fabrication processes limit their development. Wearable resistance, pressure, and strain sensors should include a compressible or stretchable substrate and conductive materials. Most importantly, they should possess high sensitivity, rapid response, wide monitoring range, skin-friendliness, biocompatibility, and durability across multiple monitoring cycles. While silica aerogels and metal aerogels offer certain advantages, these materials do not meet all requirements, such as skin affinity and the potential for production from renewable raw material sources.

[0004] Unlike traditional aerogels, biomass-based aerogels offer advantages such as being economical, environmentally friendly, and virtually inexhaustible. In recent years, research and development of renewable and biodegradable biomass-based aerogel materials have been continuously undertaken. Therefore, this invention proposes a method for synthesizing nanoporous biomass-based aerogels based on carboxymethyl chitosan. Summary of the Invention

[0005] The purpose of this invention is to provide a nanoporous aerogel based on carboxymethyl chitosan, its preparation method and application, and to provide a preparation method for biomass-based aerogels, solving the problems of difficult-to-obtain raw materials, high cost and complex preparation process of existing aerogels, while achieving high sensitivity of aerogel sensors.

[0006] To achieve the above objectives, the present invention provides a nanoporous aerogel based on carboxymethyl chitosan, comprising the following components by weight: 2.5 parts deionized water, 0.075 parts carboxymethyl chitosan (CMC), 0.0075-0.0225 parts carboxylated multi-walled carbon nanotubes (C-CNT), 0.01125 parts glutaraldehyde (GA), 0.01 parts poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT:PSS), and 10 parts dimethyl sulfoxide (DMSO).

[0007] This invention also provides a method for preparing the above-mentioned carboxymethyl chitosan-based nanoporous aerogel, comprising the following steps:

[0008] S1. Place deionized water and carboxymethyl chitosan in a beaker and stir magnetically until there is no obvious solid in the carboxymethyl chitosan. Then add carboxylated multi-walled carbon nanotubes and continue stirring magnetically. After stirring, perform ultrasonic treatment.

[0009] S2. Pour the mixed solution obtained by ultrasound in S1 into a mold, add glutaraldehyde and stir to obtain a hydrogel material, and freeze-dry it in a directional manner to obtain CMC / C-CNT aerogel.

[0010] S3. Pour the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) solution into a mold to obtain a hydrogel material, and freeze-dry it to obtain PEDOT:PSS aerogel.

[0011] S4. Place the PEDOT:PSS aerogel obtained in S3 into a beaker and tear it into pieces with tweezers. Add dimethyl sulfoxide solution and then process it with a high-speed homogenizer. Finally, perform ultrasonic treatment to obtain a mixed solution.

[0012] S5. Place the CMC / C-CNT aerogel obtained in S2 into the mixed solution obtained by ultrasound in S4, then place it in a vacuum drying oven for vacuum impregnation and vacuum drying. Repeat the operation 3 times to obtain carboxymethyl chitosan nano-aerogel.

[0013] Preferably, in S2, the directional freeze-drying method is as follows: the hydrogel material is placed on a copper block in liquid nitrogen and frozen, and then placed in a refrigerated dryer for 24 hours of freeze-drying.

[0014] Preferably, in S3, the freeze-drying method is as follows: the hydrogel material is placed in a refrigerator and frozen for 24 hours, and then placed in a refrigerated dryer for 24 hours of freeze-drying.

[0015] Preferably, in S4, the high-speed homogenizer processes the mixture by mixing for 2 minutes, stopping for 2 minutes, and repeating this cycle 5 times.

[0016] Preferably, in step S5, after vacuum impregnation for 45 minutes, the sample is placed in a vacuum drying oven and dried under vacuum at 65°C for 72 hours.

[0017] The present invention also provides the application of the above-mentioned carboxymethyl chitosan-based nanoporous aerogel in the preparation of aerogel sensors.

[0018] This invention is based on the self-crosslinking of carboxymethyl chitosan and the interaction of ionic and hydrogen bonds between carboxylated multi-walled carbon nanotubes and carboxymethyl chitosan. Carboxymethyl chitosan (CMC) is used as the matrix, and carboxylated carbon nanotubes (C-CNTs) are used as the internal conductive material and strength-enhancing material. A hydrogel is formed under the action of crosslinking agent GA, and CMC / C-CNT aerogel is prepared by directional freeze-drying. Then, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT:PSS) is impregnated to obtain CMC / C-CNT / PEDOT:PSS as the external conductive material, which forms a double conductive network with the internal C-CNTs, thus preparing an aerogel with excellent conductivity and mechanical properties.

[0019] Therefore, the nanoporous aerogel based on carboxymethyl chitosan provided by the present invention, its preparation method, and its application have the following beneficial effects:

[0020] (1) Chitosan is the second most abundant biopolymer on Earth after cellulose. It is a low-cost, green, non-toxic natural polymer with abundant active groups. Compared with the aerogels prepared using silica and metal materials in the past, the raw materials used in this invention are lower in cost and easier to obtain.

[0021] (2) In this invention, flexible carboxymethyl chitosan (CMC) is combined with rigid carboxylated multi-walled carbon nanotubes (C-CNT), and its internal structure is changed by means of directional freezing, so as to prepare CMC / C-CNT aerogel with excellent mechanical properties; it is combined with poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT:PSS) by impregnation method to construct PEDOT:PSS@CMC / C-CNT conductive aerogel with internal and external double conductive networks;

[0022] (3) The aerogel obtained by this invention was used to prepare a sensor. The prepared sensor has high mechanical and electrical properties, achieving a 1.34 × 10⁻⁶ ohmmeter. -4 High conductivity (s / cm) and 7.33 kPa -1 High sensitivity.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 The image shows the morphology of the CMC / C-CNT aerogel obtained in Example 2.

[0025] Figure 2 This is a schematic diagram illustrating the preparation of the CMC / C-CNT aerogel in Example 2;

[0026] Figure 3 This is a schematic diagram illustrating the preparation of the carboxymethyl chitosan aerogel material in Example 3;

[0027] Figure 4 Compression cycle curve of the aerogel sensor prepared using the carboxymethyl chitosan aerogel material obtained in Example 2;

[0028] Figure 5 The maximum stress and height retention energy loss coefficient variation curves are shown for the aerogel sensor prepared using the carboxymethyl chitosan aerogel material obtained in Example 2.

[0029] Figure 6 The response and recovery time curves of the aerogel sensor prepared using the carboxymethyl chitosan aerogel material obtained in Example 2 are shown.

[0030] Figure 7 The image shows the effect of an aerogel sensor prepared using the carboxymethyl chitosan aerogel material obtained in Example 2 on monitoring the finger bending response rate.

[0031] Figure 8 The image shows the effect of an aerogel sensor prepared using the carboxymethyl chitosan aerogel material obtained in Example 2 on monitoring the wrist movement response rate.

[0032] Figure 9 The graph shows the effect of an aerogel sensor prepared using the carboxymethyl chitosan aerogel material obtained in Example 2 on monitoring the response rate during human swallowing.

[0033] Figure 10 The image shows the effect of an aerogel sensor prepared using the carboxymethyl chitosan aerogel material obtained in Example 2 on monitoring the response rate of human cheek puffing.

[0034] Figure 11 The image shows the effect of an aerogel sensor prepared using the carboxymethyl chitosan aerogel material obtained in Example 2 to monitor the response rate of a person frowning. Detailed Implementation

[0035] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims and are all within the protection scope of the present invention.

[0036] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0037] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0038] Unless otherwise specified, the reagents, instruments, and equipment used in this invention are all commonly used by those skilled in the art.

[0039] Example 1

[0040] This embodiment provides a method for preparing a nanoporous aerogel based on carboxymethyl chitosan, using the raw materials in the weight proportions listed in Table 1:

[0041] Table 1. Synthetic aerogels of carboxymethyl chitosan (parts by weight)

[0042]

[0043] The preparation method includes the following steps:

[0044] S1. Place the weighed deionized water and carboxymethyl chitosan in a beaker and stir magnetically for 0.5 hours until there is no obvious solid in the carboxymethyl chitosan. Add the measured amount of carboxylated multi-walled carbon nanotubes and stir magnetically for 1 hour. After stirring, sonicate the mixed solution for 1 hour.

[0045] S2. Pour the mixed solution obtained by ultrasound in S1 into a mold, add the measured amount of glutaraldehyde and stir quickly to obtain a hydrogel material. Place the hydrogel material on a copper block in liquid nitrogen to freeze and then put it into a freeze dryer for 24 hours to freeze dry the hydrogel.

[0046] S3. Pour the measured poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) solution into a mold to obtain an aerogel material. Then, freeze it in a refrigerator for 24 hours and freeze-dry it in a refrigerated dryer for 24 hours to obtain an aerogel.

[0047] S4. Place the aerogel obtained in S3 into a beaker and tear it into pieces with tweezers. Add the measured dimethyl sulfoxide solution and treat it with a high-speed homogenizer for 2 minutes, then stop for 2 minutes. Repeat this process 5 times. Finally, place the beaker into an ultrasonic instrument and sonicate it for 1 hour.

[0048] S5. Place the hydrogel obtained in S2 into the mixed solution obtained by ultrasound in S4, place it in a vacuum drying oven for 45 minutes for vacuum impregnation, place it in a vacuum drying oven at 65°C for 72 hours, and repeat the operation 3 times to obtain a high-performance carboxymethyl chitosan aerogel material.

[0049] Example 2

[0050] This embodiment provides a method for preparing a nanoporous aerogel based on carboxymethyl chitosan, using the raw materials in the weight proportions listed in Table 2:

[0051] Table 2. Synthetic aerogels made from carboxymethyl chitosan (parts by weight)

[0052]

[0053]

[0054] The preparation method includes the following steps:

[0055] S1. Place the weighed deionized water and carboxymethyl chitosan in a beaker and stir magnetically for 0.5 hours until there is no obvious solid in the carboxymethyl chitosan. Add the measured amount of carboxylated multi-walled carbon nanotubes and stir magnetically for 1 hour. After stirring, sonicate the mixed solution for 1 hour.

[0056] S2. Pour the mixed solution obtained by ultrasound in S1 into a mold, add the measured amount of glutaraldehyde and stir quickly to obtain a hydrogel material. Place the hydrogel material on a copper block in liquid nitrogen to freeze and then put it into a freeze dryer for 24 hours to freeze dry the hydrogel.

[0057] S3. Pour the measured poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) solution into a mold to obtain an aerogel material. Then, freeze it in a refrigerator for 24 hours and freeze-dry it in a refrigerated dryer for 24 hours to obtain an aerogel.

[0058] S4. Place the aerogel obtained in S3 into a beaker and tear it into pieces with tweezers. Add the measured dimethyl sulfoxide solution and treat it with a high-speed homogenizer for 2 minutes, then stop for 2 minutes. Repeat this process 5 times. Finally, place the beaker into an ultrasonic instrument and sonicate it for 1 hour.

[0059] S5. Place the hydrogel obtained in S2 into the mixed solution obtained by ultrasound in S4, place it in a vacuum drying oven for 45 minutes for vacuum impregnation, place it in a vacuum drying oven at 65°C for 72 hours, and repeat the operation 3 times to obtain a high-performance carboxymethyl chitosan aerogel material.

[0060] Example 3

[0061] This embodiment provides a method for preparing a nanoporous aerogel based on carboxymethyl chitosan, using the raw materials in the weight proportions listed in Table 3:

[0062] Table 3. Synthetic aerogels of carboxymethyl chitosan (parts by weight)

[0063]

[0064] The preparation method includes the following steps:

[0065] S1. Place the weighed deionized water and carboxymethyl chitosan in a beaker and stir magnetically for 0.5 hours until there is no obvious solid in the carboxymethyl chitosan. Add the measured amount of carboxylated multi-walled carbon nanotubes and stir magnetically for 1 hour. After stirring, sonicate the mixed solution for 1 hour.

[0066] S2. Pour the mixed solution obtained by ultrasound in S1 into a mold, add the measured amount of glutaraldehyde and stir quickly to obtain a hydrogel material. Place the hydrogel material on a copper block in liquid nitrogen to freeze and then put it into a freeze dryer for 24 hours to freeze dry the hydrogel.

[0067] S3. Pour the measured poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) solution into a mold to obtain an aerogel material. Then, freeze it in a refrigerator for 24 hours and freeze-dry it in a refrigerated dryer for 24 hours to obtain an aerogel.

[0068] S4. Place the aerogel obtained in S3 into a beaker and tear it into pieces with tweezers. Add the measured dimethyl sulfoxide solution and treat it with a high-speed homogenizer for 2 minutes, then stop for 2 minutes. Repeat this process 5 times. Finally, place the beaker into an ultrasonic instrument and sonicate it for 1 hour.

[0069] S5. Place the hydrogel obtained in S2 into the mixed solution obtained by ultrasound in S4, place it in a vacuum drying oven for 45 minutes for vacuum impregnation, place it in a vacuum drying oven at 65°C for 72 hours, and repeat the operation 3 times to obtain a high-performance carboxymethyl chitosan aerogel material.

[0070] The CMC / C-CNT aerogel material prepared in Example 2 was placed on an extremely fine leaf petiole, and the results were as follows: Figure 1 As shown. By Figure 1 It is known that CMC / C-CNT aerogels can be supported by extremely fine petioles, exhibiting the characteristic of being lightweight.

[0071] Figure 2 The preparation process of CMC / C-CNT aerogel in Example 2 is as follows: carboxymethyl chitosan (CMC) is selected as the matrix, and carboxylated multi-walled carbon nanotubes (C-CNT) are selected as the internal conductive material. Under the action of crosslinking agent GA, hydrogel is formed, and aerogel is obtained by directional freeze drying.

[0072] Figure 3 The preparation process of the carboxymethyl chitosan aerogel material in Example 3 is as follows: (1) PEDOT:PSS is freeze-dried and then shredded. A mixed solution of dimethyl sulfoxide and PEDOT:PSS is prepared using a high-speed homogenizer and an ultrasonic instrument. (2) CMC / C-CNT aerogel is immersed in the dimethyl sulfoxide (DMSO) and PEDOT:PSS solution to construct an internal and external synergistic double conductive network and obtain PEDOT:PSS@CMC / C-CNT conductive aerogel.

[0073] The carboxymethyl chitosan aerogel material obtained in Example 2 was used to prepare an aerogel sensor. Electrodes were printed using conductive silver paste and polydimethylsiloxane (PDMS) as raw materials, and a flexible strain sensor was assembled using PEDOT:PSS@CMC / C-CNT aerogel as the sensing active material.

[0074] Stress-strain experiments were conducted on the fabricated aerogel sensor, and the compression cycle performance curve is shown below. Figure 4 As shown in the figure, the legend represents the number of cycles; the curves showing the changes in maximum stress and height retention energy loss coefficient are as follows. Figure 5 As shown. By Figure 4 and Figure 5 It can be seen that the maximum stress of the 20% CM C / C-CNT aerogel remains at 88%, and the height remains at 84%.

[0075] Sensitivity tests were conducted on the prepared aerogel sensor, and the response and recovery time curves of the sensor are shown in the figure below. Figure 6 As shown. By Figure 6 It is evident that the aerogel prepared by this invention possesses excellent responsiveness.

[0076] The prepared aerogel sensor was used to conduct motion response monitoring experiments on various parts of the human body. The effect of the sensor monitoring the finger bending response rate is shown in the figure below. Figure 7 As shown in the figure, the sensor monitors the wrist movement response rate. Figure 8 As shown in the figure, the sensor's response rate during human swallowing is illustrated in the diagram. Figure 9 As shown in the figure, the sensor monitors the response rate of a person's cheek puffing out. Figure 10 As shown in the figure, the sensor detects the response rate of a person frowning. Figure 11 As shown. By Figures 7-11 It is known that the sensor has a good response to human movement and can monitor the movement of various parts of the human body.

[0077] Therefore, this invention discloses a nanoporous aerogel based on carboxymethyl chitosan, its preparation method, and its application. Using CMC as the matrix and C-CNT as the internal conductive material, a hydrogel is formed under the action of the crosslinking agent GA. The aerogel is then obtained through directional freeze-drying. Subsequently, PEDOT:PSS is coated to obtain CMC / C-CNT / PEDOT:PSS as the external conductive material, forming a dual conductive network with the internal C-CNT. This produces an aerogel with excellent conductivity and mechanical properties. The prepared aerogel is used to fabricate a sensor, which exhibits high mechanical and electrical properties, achieving a conductivity of 1.34 × 10⁻⁶. -4 High conductivity (s / cm) and 7.33 kPa -1 High sensitivity.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a carboxymethyl chitosan-based nanoporous aerogel, characterized by: By weight, it includes the following components: 2.5 parts deionized water, 0.075 parts carboxymethyl chitosan, 0.0075-0.0225 parts carboxylated multi-walled carbon nanotubes, 0.01125 parts glutaraldehyde, 0.01 parts poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid), and 10 parts dimethyl sulfoxide. The preparation method includes the following steps: S1. Place deionized water and carboxymethyl chitosan in a beaker and stir magnetically until there is no obvious solid in the carboxymethyl chitosan. Then add carboxylated multi-walled carbon nanotubes and continue stirring magnetically. After stirring, perform ultrasonic treatment. S2. Pour the mixed solution obtained by ultrasound in S1 into a mold, add glutaraldehyde and stir to obtain a hydrogel material, and freeze-dry it in a directional manner to obtain CMC / C-CNT aerogel. S3. Pour the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) solution into a mold to obtain a hydrogel material, and freeze-dry it to obtain PEDOT:PSS aerogel. S4. Place the PEDOT:PSS aerogel obtained in S3 into a beaker and tear it into pieces with tweezers. Add dimethyl sulfoxide solution and then process it with a high-speed homogenizer. Finally, perform ultrasonic treatment to obtain a mixed solution. S5. Place the CMC / C-CNT aerogel obtained in S2 into the mixed solution obtained by ultrasound in S4, then place it in a vacuum drying oven for vacuum impregnation and vacuum drying. Repeat the operation 3 times to obtain carboxymethyl chitosan nano-aerogel.

2. The method for preparing a carboxymethyl chitosan-based nanoporous aerogel according to claim 1, characterized by, In S2, the directional freeze-drying method is as follows: the hydrogel material is placed on a copper block in liquid nitrogen and frozen, and then placed in a refrigerated dryer for 24 hours of freeze-drying.

3. The method for preparing a nanoporous aerogel based on carboxymethyl chitosan according to claim 1, characterized in that, In S3, the freeze-drying method is as follows: the hydrogel material is placed in a refrigerator and frozen for 24 hours, and then placed in a freeze dryer for 24 hours of freeze-drying.

4. The method for preparing a nanoporous aerogel based on carboxymethyl chitosan according to claim 1, characterized in that, In S4, the high-speed homogenizer processes the mixture by mixing for 2 minutes, stopping for 2 minutes, and repeating this cycle 5 times.

5. The method for preparing a nanoporous aerogel based on carboxymethyl chitosan according to claim 1, characterized in that, In S5, after vacuum impregnation for 45 minutes, it is placed in a vacuum drying oven and dried under vacuum at 65°C for 72 hours.

6. The application of the nanoporous aerogel prepared by the method for preparing carboxymethyl chitosan-based nanoporous aerogel as described in claim 1, characterized in that, The nanoporous aerogel is used to prepare aerogel sensors.

Images