Multifunctional composite ionic gel, preparation method thereof and application of multifunctional composite ionic gel in multifunctional device

Abstract

The invention discloses multifunctional composite ionic gel, a preparation method thereof and application of the multifunctional composite ionic gel in multifunctional devices, and belongs to the technical field of multifunctional device materials. The preparation method comprises the following steps: adding 5 parts by mass of a polyvinylidene fluoride-hexafluoropropylene copolymer and 1-4 parts by mass of a fluorine-containing hydrophobic ionic liquid into 0.05-0.5 part by mass of a filler dissolving solution, uniformly mixing, adding 0.15 part by mass of a cross-linking agent, reacting, and drying to obtain multifunctional composite ionic gel; wherein the filler is poly (3, 4-ethylenedioxythiophene)-polystyrolsulfon acid, a multiwalled carbon nanotube or conductive carbon black. The multifunctional composite ionic gel has excellent thermal / near-infrared light response shape memory performance, the shape fixing rate and the recovery rate can reach 98% or above, objects with the self weight being 22 times or above can be lifted, and real-time monitoring of the actuating process is supported; meanwhile, the sensor can be used as a strain sensor to realize underwater motion monitoring. The self-powered pressure sensor constructed by using the multifunctional composite ionic gel can be applied to the fields of health monitoring and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of multifunctional device materials, and particularly relates to a multifunctional composite ionic gel, a preparation method thereof and application thereof in multifunctional devices. BACKGROUND

[0002] With the rapid development of science and technology, the performance requirements of materials have changed from single function to multifunctional integration. Multifunctional integrated materials can realize multiple functions such as sensing, driving and energy supply in the same system. However, the mutual interference between functions may affect the overall performance of the material. Therefore, developing materials that can integrate multiple functions while maintaining basic performance has become an important frontier in materials science research. Integrating sensing and driving functions has become a key step in expanding the application range of flexible electronic devices. Shape memory materials can recover their preset shape under specific stimuli, making them have important application value in the fields of intelligent actuators and soft robots. However, the driving performance and process monitoring of traditional soft actuators usually rely on camera systems and image processing technology, which has the problems of low efficiency and poor applicability in low light environments. If the sensing function is integrated into the soft actuator, the deformation degree can be accurately obtained in real time, and automatic control of the actuation process can be realized based on the feedback signal.

[0003] However, how to realize efficient strain sensing in shape memory materials without affecting their shape recovery ability, and how to efficiently integrate multiple functions in a single material system, are key problems that need to be solved. Moreover, traditional sensors usually require external power supply, which limits their use in some application scenarios. Friction nanogenerators based on tribology and interfacial charge transfer can overcome the limitations of traditional power sources and collect various mechanical movements such as human motion, friction, vibration, etc. to power self-powered sensor devices. However, how to efficiently integrate it with shape memory performance in a single system to cooperatively realize driving, sensing and self-powering functions still faces challenges such as mutual interference of functional modules, low efficiency and complex system design. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a multifunctional composite ionic gel, a preparation method thereof and application thereof in multifunctional devices, to solve the technical problem that existing flexible actuators cannot integrate driving and sensing functions.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] The first aspect of the present application discloses a preparation method of multifunctional composite ionic gel, wherein 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 1-4 parts of fluorine-containing hydrophobic ionic liquid are added into 0.05-0.5 parts of a dissolving solution of fillers, and then 0.15 parts of a crosslinking agent is added for reaction, and then drying is performed to obtain the multifunctional composite ionic gel.

[0007] Preferably, the filler is poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, multi-walled carbon nanotube or conductive carbon black.

[0008] Preferably, the preparation method of the dissolving solution of fillers is as follows: 0.05-0.5 parts of fillers are added into 100 parts of a solvent for magnetic stirring for 12 hours, and then ultrasonic dispersion is performed to obtain a dispersion solution of fillers.

[0009] Preferably, the solvent is N,N-dimethylformamide, dimethyl sulfoxide or N,N-dimethylacetamide.

[0010] Further preferably, the reaction condition is as follows: stirring reaction is performed at 60-80 DEG C for 2-4 hours.

[0011] Preferably, the fluorine-containing hydrophobic ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium hexafluorophosphate or 1-aminoethyl-3-methylimidazolium hexafluorophosphate.

[0012] Preferably, the crosslinking agent is trimethylhexanediamine, xylene diamine, 1,6-diamine-hexane, ethylenediamine or diethylenetriamine.

[0013] The second aspect of the present application discloses the multifunctional composite ionic gel prepared by the above preparation method.

[0014] Preferably, the shape fixing rate and the shape recovery rate of the multifunctional composite ionic gel are both greater than 98%.

[0015] The third aspect of the present application discloses a strain sensor comprising the multifunctional composite ionic gel.

[0016] The fourth aspect of the present application discloses a friction nanogenerator, wherein the multifunctional composite ionic gel is used as a conductive layer and a negative friction layer material.

[0017] The fifth aspect of the present application discloses a self-powered pressure sensor comprising the friction nanogenerator.

[0018] Preferably, the sensitivity of the self-powered pressure sensor in the pressure range of 0.43-2.12 kPa is 5.890 V kPa. -1The self-powered pressure sensor adopts a multifunctional composite ionic gel prepared from 0.25 parts of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer, 2 parts of ionic liquid, and 0.15 parts of trimethylhexanediamine.

[0019] In a sixth aspect of the present application, the use of the multifunctional composite ionic gel, the strain sensor, the friction nanogenerator, or the self-powered pressure sensor in the preparation of a multifunctional device is disclosed.

[0020] Preferably, the multifunctional device is a flexible wearable device or a flexible actuator.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] The preparation method of the multifunctional composite ionic gel provided by the present application uses polyvinylidene fluoride-hexafluoropropylene copolymer as a base material, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, multi-walled carbon nanotubes, or conductive carbon black as a filler, combines fluorine-containing hydrophobic ionic liquid and a crosslinking agent, and prepares the multifunctional composite ionic gel through a solution casting method. In this method, 1) poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, multi-walled carbon nanotubes, or conductive carbon black is used as a filler, which can adjust the mechanical, photothermal, and conductive properties of the composite ionic gel, and endow the composite material with excellent near-infrared light response shape memory performance, while improving the output performance of the composite ionic gel-based friction nanogenerator device. 2) Both polyvinylidene fluoride-hexafluoropropylene copolymer and fluorine-containing hydrophobic ionic liquid contain a large number of fluorine atoms, which endows the multifunctional composite ionic gel with good hydrophobicity, laying a foundation for its underwater sensing. The multifunctional composite ionic gel prepared by this method has excellent thermal / near-infrared light response shape memory performance and underwater stability, and the shape fixing rate and shape recovery rate both reach 98%. Using the light response shape memory performance of the multifunctional composite ionic gel, it can be used as a soft actuator to lift an object that is several tens of times heavier than itself, and it can accurately monitor and control the actuation process. The multifunctional composite ionic gel is used as a conductive layer and negative friction material to assemble a single-layer friction nanogenerator with silica gel, which has high sensitivity, integrates actuation, sensing, and self-powering functions, and can be used as a self-powered pressure sensor to monitor human motion in complex dynamic scenes, and is used in flexible wearable devices.

[0023] The strain sensor provided by the present application has excellent water resistance and can monitor human motion in a water environment to send a distress signal according to Morse code, which greatly expands the application of the multifunctional composite ionic gel in complex environments.

[0024] The self-powered pressure sensor provided by the application can generate different output voltage signals with different bending angles of joints such as fingers and wrists, and can be applied in wearable and health monitoring fields. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Microscopic morphology diagrams of multifunctional composite ionic gels prepared under different conditions of the application; wherein, (a) is the cross-sectional microscopic morphology of the multifunctional composite ionic gel prepared in Example 2, and (b) is the cross-sectional microscopic morphology of the multifunctional composite ionic gel prepared in Example 5;

[0026] Figure 2 Schematic diagrams of thermal / near-infrared light dual-response shape memory processes of multifunctional composite ionic gels prepared under different conditions of the application; wherein, (a) is a thermal response shape memory behavior process diagram of the multifunctional composite ionic gel prepared in Example 1, and (b) is a near-infrared light response shape memory behavior process diagram of the multifunctional composite ionic gel prepared in Example 2;

[0027] Figure 3 Schematic diagrams of processes of lifting heavy objects by the multifunctional composite ionic gel prepared in Example 2 of the application as a soft driver; wherein, (a) is a driver test schematic diagram, (b-d) are schematic diagrams of lifting different weight objects under the near-infrared light response of Example 2, (e) is a relative resistance and light response shape recovery rate relationship curve, and (f) is a relationship between the relative resistance, length and light response shape recovery rate;

[0028] Figure 4 Relative resistance curve diagrams of the multifunctional composite ionic gel prepared in Example 2 of the application in underwater sensing; wherein, (a) is the mass change of the multifunctional composite ionic gel of Example 2 after being soaked in water for different times, (b) is the stress-strain comparison curve of the multifunctional composite ionic gel of Example 2 after being soaked in water for 180 min and the original one, (c) is a test principle diagram of underwater sensing, (d-f) are relative resistance curves corresponding to the bending of fingers, wrists and arms in water, (g) is a relative resistance change curve corresponding to the Morse code "SOS", (h) is an underwater sensing application scenario, and (i) is a relative resistance curve corresponding to the Morse code "HELP";

[0029] Figure 5 Output performance curve diagrams of single-layer friction nanogenerators constructed by the multifunctional composite ionic gels prepared under different conditions of the application; wherein, (a) is an output voltage curve diagram, and (b) is a transferred charge amount curve diagram;

[0030] Figure 6 Self-powered pressure sensing performance curve diagram of the friction nanogenerator constructed by the multifunctional composite ionic gel prepared in Example 2 of the application;

[0031] Figure 7 Application diagram of self-powered pressure sensor constructed by multifunctional composite ionic gel prepared in Example 2 of the present application in human motion monitoring; wherein (a) is the relationship between wrist bending angle and output voltage, (b) is the relationship between finger bending angle and output voltage, (c) is the relationship between knee bending angle and output voltage, and (d) is the relationship between arm bending angle and output voltage. DETAILED DESCRIPTION

[0032] To enable persons skilled in the art to understand the features and effects of the present application, the following only generally describes and defines the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein have the usual meanings understood by those skilled in the art of the present application, and in the event of conflict, the definitions in the present specification shall prevail.

[0033] Theories or mechanisms described and disclosed herein, whether correct or not, should not be considered limiting on the scope of the present application, i.e., the present application can be practiced without regard to any particular theory or mechanism.

[0034] Herein, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, amounts, contents and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values (including integers and fractions) within the range.

[0035] Herein, unless otherwise specified, "comprise", "include", "contain", "have" or similar words encompass the meaning of "consist of" and "consist essentially of", for example, "A comprises a" encompasses the meaning of "A comprises a and other" and "A comprises only a".

[0036] Herein, for the sake of brevity, all possible combinations of the technical features in each embodiment or example are not described. Therefore, as long as the combinations of the technical features do not contradict each other, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope disclosed in the present specification.

[0037] The present application provides a preparation method of multifunctional composite ionic gel, comprising the following steps:

[0038] 1) 0.05-0.5 parts of filler was added to 100 parts of solvent, and stirred by magnetic force at room temperature for 12 h, and ultrasonically dispersed for 30 min to obtain a uniform dispersion liquid;

[0039] The filler includes but is not limited to poly (3, 4-ethylenedioxythiophene) -polystyrene sulfonic acid, multi-walled carbon nanotubes or conductive carbon black; the amount of filler can be specifically 0.05 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts or 0.5 parts; the solvent includes but is not limited to N, N-dimethylformamide, dimethyl sulfoxide or N, N-dimethylacetamide; the room temperature refers to a temperature of about 20-35℃, or about 23-28℃, or about 25℃, which can be 20℃, 25℃, 30℃ or 33℃.

[0040] 2) 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 1-4 parts of fluorine-containing hydrophobic ionic liquid are added to the uniform dispersion solution obtained in step 1), and heated and stirred at 60-80℃ until completely dissolved to obtain a composite solution;

[0041] The fluorine-containing hydrophobic ionic liquid includes but is not limited to 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium hexafluorophosphate or 1-aminoethyl-3-methylimidazolium hexafluorophosphate; the amount of fluorine-containing hydrophobic ionic liquid can be specifically 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts or 4 parts; the temperature of heating and stirring can be specifically 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, 66℃, 67℃, 68℃, 69℃, 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃ or 80℃.

[0042] 3) 0.15 parts of crosslinking agent are added to the composite solution obtained in step 2), and further magnetically stirred at 60-80℃ for 2-4h, and then placed in an oven at 80℃ for 24h to obtain a multifunctional composite ionic gel;

[0043] The crosslinking agent includes but is not limited to trimethylhexanediamine, xylene diamine, 1, 6-diamine-hexane, ethylenediamine or diethylenetriamine; the temperature of magnetic stirring can be specifically 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, 66℃, 67℃, 68℃, 69℃, 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃ or 80℃; the time of magnetic stirring can be specifically 2h, 2.5h, 3h, 3.5h or 4h.

[0044] The application will be further described in connection with the following specific examples. It should be understood that the examples are intended to illustrate the application and are not intended to limit the scope of the application. Moreover, it should be understood that various modifications and changes can be made to the application by those skilled in the art upon reading the contents of this specification, and such equivalent forms are intended to fall within the scope of the application as defined in the appended claims.

[0045] The following examples use apparatuses and devices that are conventional in the art. The experimental methods in the following examples, unless otherwise specified, are generally carried out under conventional conditions, or under conditions recommended by the manufacturers. The following examples use various raw materials, unless otherwise specified, and use conventional commercially available products, which are of conventional specifications in the art. In the specification of the present application and in the following examples, unless otherwise specified, "%" means mass percent, "parts" means mass parts, and the ratio means mass ratio.

[0046] I. Preparation of multifunctional composite ionic gel

[0047] The multifunctional composite ionic gels of Examples 1 to 15 and Comparative Example 1 were prepared according to Table 1.

[0048] Table 1 Multifunctional composite ionic gels prepared in different examples and comparative examples

[0049]

[0050]

[0051] Example 1

[0052] 1) 0.25 parts of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid was added to 100 parts of dimethyl sulfoxide, and stirred magnetically at 25°C for 12 h, and ultrasonically dispersed for 30 min to obtain a uniform dispersion liquid;

[0053] 2) 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 1 part of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide were added to the uniform dispersion liquid obtained in step 1), and heated and stirred at 70°C for 3 h until completely dissolved;

[0054] 3) 0.15 parts of trimethylhexanediamine was added to the composite solution obtained in step 2), and further stirred magnetically at 70°C for 3 h to obtain a viscous solution;

[0055] 4) The viscous solution obtained in step 3) was poured into a culture dish, and placed in an oven at 80°C for 24 h to obtain a multifunctional composite ionic gel.

[0056] Example 2

[0057] 1) 0.25 parts of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid was added into 100 parts of dimethyl sulfoxide, stirred magnetically at 30 °C for 12 h, and ultrasonically dispersed for 30 min to obtain a uniform dispersion liquid;

[0058] 2) 5 parts of poly(vinylidene fluoride-hexafluoropropylene) copolymer and 2 parts of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide were added into the uniform dispersion liquid obtained in step 1), and heated and stirred at 60 °C for 4 h until completely dissolved;

[0059] 3) 0.15 parts of trimethylhexanediamine was added into the composite solution obtained in step 2), and further magnetically stirred at 60 °C for 4 h to obtain a viscous solution;

[0060] 4) The viscous solution obtained in step 3) was poured into a culture dish, and placed in an oven at 80 °C for 24 h to obtain a multifunctional composite ionic gel (PI 40 P5).

[0061] Example 3

[0062] 1) 0.15 parts of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid was added into 100 parts of dimethyl sulfoxide, stirred magnetically at 28 °C for 12 h, and ultrasonically dispersed for 30 min to obtain a uniform dispersion liquid;

[0063] 2) 5 parts of poly(vinylidene fluoride-hexafluoropropylene) copolymer and 3 parts of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide were added into the uniform dispersion liquid obtained in step 1), and heated and stirred at 80 °C for 2 h until completely dissolved;

[0064] 3) 0.15 parts of trimethylhexanediamine was added into the composite solution obtained in step 2), and further magnetically stirred at 80 °C for 2 h to obtain a viscous solution;

[0065] 4) The viscous solution obtained in step 3) was poured into a culture dish, and placed in an oven at 80 °C for 24 h to obtain a multifunctional composite ionic gel.

[0066] Example 4

[0067] 1) 0.05 parts of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid was added into 100 parts of dimethyl sulfoxide, stirred magnetically at 28 °C for 12 h, and ultrasonically dispersed for 30 min to obtain a uniform dispersion liquid;

[0068] 2) 5 parts of poly(vinylidene fluoride-hexafluoropropylene) copolymer and 4 parts of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide were added into the uniform dispersion liquid obtained in step 1), and heated and stirred at 60 °C for 4 h until completely dissolved;

[0069] 3) 0.15 parts of trimethylhexanediamine were added to the composite solution obtained in step 2), and further magnetic stirring reaction was carried out at 60°C for 4h to obtain a viscous solution;

[0070] 4) The viscous solution obtained in step 3) was poured into a culture dish and placed in an oven at 80°C for 24h to obtain a multifunctional composite ionic gel.

[0071] Example 5

[0072] 1) 0.5 parts of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid were added to 100 parts of dimethyl sulfoxide, magnetic stirring was carried out at 25°C for 12h, and ultrasonic dispersion was carried out for 30min to obtain a uniform dispersion liquid;

[0073] 2) 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 2 parts of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide were added to the uniform dispersion liquid obtained in step 1), and heating stirring was carried out at 70°C for 2h until complete dissolution;

[0074] 3) 0.15 parts of trimethylhexanediamine were added to the composite solution obtained in step 2), and further magnetic stirring reaction was carried out at 70°C for 3h to obtain a viscous solution;

[0075] 4) The viscous solution obtained in step 3) was poured into a culture dish and placed in an oven at 80°C for 24h to obtain a multifunctional composite ionic gel.

[0076] Example 6

[0077] 1) 0.25 parts of multi-walled carbon nanotubes were added to 100 parts of dimethyl sulfoxide, and ultrasonic dispersion was carried out for 30min to obtain a multi-walled carbon nanotube dispersion liquid;

[0078] 2) 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 2 parts of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide were added to the uniform dispersion liquid obtained in step 1), and heating stirring was carried out at 60°C for 4h until complete dissolution;

[0079] 3) 0.15 parts of trimethylhexanediamine were added to the composite solution obtained in step 2), and further magnetic stirring reaction was carried out at 60°C for 4h to obtain a viscous solution;

[0080] 4) The viscous solution obtained in step 3) was poured into a culture dish and placed in an oven at 80°C for 24h to obtain a multifunctional composite ionic gel.

[0081] Example 7

[0082] 1) 0.15 parts of conductive carbon black was added into 100 parts of dimethyl sulfoxide by mass fraction, and ultrasonic dispersion was carried out for 30 min to obtain a carbon black dispersion liquid;

[0083] 2) 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 3 parts of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide were added into the carbon black dispersion liquid obtained in step 1), and heating and stirring were carried out at 70°C for 3 h until complete dissolution;

[0084] 3) 0.15 parts of trimethylhexanediamine was added into the composite solution obtained in step 2), and further magnetic stirring reaction was carried out at 70°C for 3 h to obtain a viscous solution;

[0085] 4) The viscous solution obtained in step 3) was poured into a culture dish, and placed in an oven at 80°C for 24 h to obtain a multifunctional composite ionic gel.

[0086] Example 8

[0087] 1) 0.25 parts of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid was added into 100 parts of N,N-dimethylacetamide by mass fraction, magnetic stirring was carried out at 25°C for 12 h, and ultrasonic dispersion was carried out for 30 min to obtain a uniform dispersion liquid;

[0088] 2) 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 2 parts of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide were added into the uniform dispersion liquid obtained in step 1), and heating and stirring were carried out at 65°C for 3 h until complete dissolution;

[0089] 3) 0.15 parts of trimethylhexanediamine was added into the composite solution obtained in step 2), and further magnetic stirring reaction was carried out at 70°C for 3 h to obtain a viscous solution;

[0090] 4) The viscous solution obtained in step 3) was poured into a culture dish, and placed in an oven at 80°C for 24 h to obtain a multifunctional composite ionic gel.

[0091] Example 9

[0092] 1) 0.25 parts of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid was added into 100 parts of N,N-dimethylformamide by mass fraction, magnetic stirring was carried out at 25°C for 12 h, and ultrasonic dispersion was carried out for 30 min to obtain a uniform dispersion liquid;

[0093] 2) 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 2 parts of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide were added into the uniform dispersion liquid obtained in step 1), and heating and stirring were carried out at 70°C for 3 h until complete dissolution;

[0094] 3) To the composite solution obtained in step 2), 0.15 parts of diaminoditolylmethane was added and further stirred magnetically at 70 °C for 3 h to obtain a viscous solution;

[0095] 4) The viscous solution obtained in step 3) was poured into a petri dish and placed in an oven at 80 °C for 24 h to obtain a multifunctional composite ionic gel.

[0096] Example 10

[0097] 1) 0.25 parts of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid was added to 100 parts of dimethyl sulfoxide by mass fraction, stirred magnetically at 25 °C for 12 h, and ultrasonically dispersed for 30 min to obtain a uniform dispersion;

[0098] 2) 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 2 parts of 1-butyl-3-methylimidazolium hexafluorophosphate were added to the uniform dispersion obtained in step 1), and heated and stirred at 70 °C for 3 h until completely dissolved;

[0099] 3) 0.15 parts of diaminoditolylmethane was added to the composite solution obtained in step 2), and further stirred magnetically at 70 °C for 3 h to obtain a viscous solution;

[0100] 4) The viscous solution obtained in step 3) was poured into a petri dish and placed in an oven at 80 °C for 24 h to obtain a multifunctional composite ionic gel.

[0101] Example 11

[0102] 1) 0.25 parts of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid was added to 100 parts of dimethyl sulfoxide by mass fraction, stirred magnetically at 25 °C for 12 h, and ultrasonically dispersed for 30 min to obtain a uniform dispersion;

[0103] 2) 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 2 parts of 1-butyl-3-methylimidazolium hexafluorophosphate were added to the uniform dispersion obtained in step 1), and heated and stirred at 70 °C for 3 h until completely dissolved;

[0104] 3) 0.15 parts of diaminoditolylmethane was added to the composite solution obtained in step 2), and further stirred magnetically at 70 °C for 3 h to obtain a viscous solution;

[0105] 4) The viscous solution obtained in step 3) was poured into a petri dish and placed in an oven at 80 °C for 24 h to obtain a multifunctional composite ionic gel.

[0106] Example 12

[0107] 1) 0.25 parts of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid was added into 100 parts of dimethyl sulfoxide, magnetically stirred at 25 °C for 12 h, and ultrasonically dispersed for 30 min to obtain a uniform dispersion liquid;

[0108] 2) 5 parts of poly(vinylidene fluoride-hexafluoropropylene) copolymer and 2 parts of 1-aminoethyl-3-methylimidazolium hexafluorophosphate were added into the uniform dispersion liquid obtained in step 1), and heated and stirred at 70 °C for 3 h until completely dissolved;

[0109] 3) 0.15 parts of ethylenediamine was added into the composite solution obtained in step 2), and further magnetically stirred and reacted at 70 °C for 3 h to obtain a viscous solution;

[0110] 4) The viscous solution obtained in step 3) was poured into a culture dish, and placed in an oven at 80 °C for 24 h to obtain a multifunctional composite ionic gel.

[0111] Example 13

[0112] The difference from Example 2 is that the amount of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is 0.05 parts, and finally a multifunctional composite ionic gel (PI 40 P1) is prepared.

[0113] Example 14

[0114] The difference from Example 2 is that the amount of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is 0.15 parts, and finally a multifunctional composite ionic gel (PI 40 P3) is prepared.

[0115] Example 15

[0116] The difference from Example 2 is that the amount of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is 0.35 parts, and finally a multifunctional composite ionic gel (PI 40 P7) is prepared.

[0117] Comparative Example 1

[0118] The difference from Example 2 is that the amount of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is 0 parts, and finally a control multifunctional composite ionic gel (PI 40 ) is prepared.

[0119] II. Exploration of the performance of multi-response shape memory composites

[0120] 1. Mechanical property characterization

[0121] The multifunctional composite ionic gels prepared in Examples 1-5 were cut into dumbbell-shaped samples (total length 35 mm, gauge length 15 mm x 2 mm x 2 mm) using a cutting die, and then the mechanical properties of the composite ionic gels were tested using a tensile testing machine, with the following tensile test parameters: tensile speed: 50 mm / min, temperature: 25°C, and at least 5 parallel samples were tested for each group of examples, and then the tensile strength and elongation at break data were obtained. Finally, the cross-sectional microstructure of the composite ionic gels was photographed using a scanning electron microscope (SEM).

[0122] Table 2 Mechanical properties of multifunctional composite ionic gels prepared under different example conditions

[0123] Sample Tensile strength (MPa) Elongation at break (%) Example 1 25.37±3.95 65.82±5.98 Example 2 22.76±2.29 251.06±37.76 Example 3 11.87±1.57 136.87±7.32 Example 4 8.32±0.38 128.05±10.64 Example 5 5.98±1.50 98±23.21

[0124] The mechanical properties of the composite ionic gels prepared under different example conditions are shown in Table 2, and the cross-sectional microstructure of the composite ionic gels of Example 2 and Example 5 is shown in Figures (a) and (b). Figure 1 As can be seen from Figures (a) and (b), poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, as a reinforcing conductive filler, is uniformly dispersed in the matrix at a low addition amount, and improves the mechanical properties and output performance of the composite ionic gel, but excessive amounts can cause agglomeration, leading to stress concentration and thus reducing the mechanical properties of the material. The ionic liquid can reduce the interaction between polymer chains and significantly improve the toughness of the composite ionic gel as a plasticizer.

[0125] 2. Thermal and light-responsive shape memory properties

[0126] 1) Thermal-responsive shape memory properties

[0127] The multifunctional composite ionic gels prepared in Examples 1-5 were tested for thermal-responsive shape memory data using a thermal cycle tensile test: first, the sample was heated to 125°C using a hot stage and stretched to 16% strain under an external force, then the sample was cooled to room temperature and the external force was removed to obtain a temporary shape, and finally the sample was reheated to 125°C using a hot stage to induce shape memory recovery, and the recovered shape was obtained. The shape fixing rate and shape recovery rate were used to evaluate the shape memory properties of the material, and the results are shown in Table 3.

[0128] Table 3 Shape memory properties of multifunctional shape memory composites prepared under different example conditions

[0129]

[0130] The results in Table 3 show that the multifunctional composite ionogel prepared by the method has excellent shape memory performance, and the shape fixation rate and shape recovery rate thereof can reach 98.4% and 98.7% or more, respectively.

[0131] 2) Photo-responsive shape memory performance

[0132] The multifunctional composite ionogel prepared in Examples 1-5 was subjected to photo-responsive shape memory test by cyclic tensile test: first, the sample was heated to a stretchable state by 808 nm near-infrared light and stretched by 27% strain under an external force, then the sample was cooled to room temperature and the external force was removed to obtain a temporary shape, and finally the sample was induced to shape memory recovery process by 808 nm near-infrared light to obtain a recovered shape.

[0133] As shown in Table 3 and Figure 2 , the shape memory composite ionogel has excellent thermal response and near-infrared light response shape memory performance, and the shape fixation rate and shape recovery under thermal response and light response conditions can reach 98% or more.

[0134] 3. Shape memory driver based on near-infrared light response

[0135] As shown in Figure 3 (a), the multifunctional composite ionogel prepared in Example 2 was stretched by 100% strain, and a clamp with a weight of 6-22 times that of the sample itself was clamped at the bottom end of the sample Figure 3 (b)-(d), the composite ionogel was irradiated with a power of 1.68 Wcm -2 , and then the relative resistance vs. light-responsive shape recovery rate curve was plotted to explore the relationship between the relative resistance, length and light-responsive shape recovery rate.

[0136] As shown in Figure 3 (b)-(d), it can be seen that after several seconds of irradiation, the clamp at the bottom end moves upward as the recovery rate of the composite ionogel gradually increases. As shown in Figure 3 (e), as the irradiation time increases, the sample gradually recovers to the original length, and the recovery rate shows an upward trend, while the resistance gradually decreases. As shown in Figure 3 (f), under different recovery length conditions, the relative resistance of the composite ionogel shows a good corresponding relationship with the recovery rate. The above results show that the composite ionogel not only has excellent photo-thermal conversion ability, but also can realize precise monitoring and regulation of the actuation process through the relationship between the recovery rate, relative resistance and length.

[0137] 4. Application in underwater sensing

[0138] The multifunctional composite ionic gel prepared in Example 2 was introduced into two copper wires at both ends and packaged with waterproof tape as a strain sensor. Subsequently, the packaged strain sensor was stably attached to the joints of the human body such as fingers, wrists, etc., to ensure that there was no obvious relative sliding between the sensor and the skin, so as to ensure the accuracy of the monitoring data. Subsequently, the experimenter regularly made bending actions on the joints of the fingers, wrists, etc. with the sensor attached, at a predetermined frequency and amplitude underwater. During the entire action process, the mass change of the multifunctional composite ionic gel, the comparison with the original stress-strain, and the resistance change of the sensor were collected and recorded in real time by a portable resistance / capacitance tester.

[0139] The results are shown in Figs. Figure 4 As shown in Figs. (a)-(b), after 180 min of immersion, the mass of the composite ionic gel hardly changed, and the mechanical properties were almost consistent, indicating that the composite ionic gel had excellent underwater stability, which was expected to be applied to underwater sensing. Figure 4 Figs. (d)-(f) show that the relative resistance of the strain sensor changed significantly with the bending of the joints of the fingers, wrists, etc. When the joints were straight, the strain on the sensor was small, and the relative resistance was at a low level. When the joints were bent, the sensor was subjected to tensile strain, the internal conductive network structure changed, the relative resistance increased, and this resistance change showed a good correspondence with the bending angle of the joints. More importantly, based on this stable and controllable resistance change characteristic, the strain sensor made of the composite ionic gel can be combined with Morse code to correspond to the dot and dash signals in Morse code by controlling the bending action duration and interval of the joints of the fingers, wrists, etc., thereby converting human actions into recognizable electrical signals to realize the transmission of specific information such as help. This characteristic opens up broad prospects for the application of the strain sensor in emergency rescue, special environment communication, etc.

[0140] 5. Application in self-powered pressure sensor

[0141] 1) Output performance

[0142] A 2.0x2.0 cm acrylic plate was used as a substrate, and the multifunctional composite ionic gels prepared in Examples 2, 13-15 and the control multifunctional composite ionic gel prepared in Comparative Example 1 were simultaneously used as negative friction layer and conductive layer materials, and silicone rubber was used as positive friction layer material to construct a contact-separation mode single-layer friction nanogenerator similar to a single electrode. The output performance was tested by an electrometer.

[0143] The results are shown in Figs. Figure 5As shown, with the increase of ionic liquid and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid content, the output performance of the corresponding triboelectric nanogenerators showed a trend of first increasing and then decreasing. Among them, the triboelectric nanogenerator constructed from the composite material prepared in Example 2 had the highest output performance.

[0144] 2) Sensing performance

[0145] A piece of polyethylene terephthalate with a width of 3.0 × 10 cm was cut, and both ends were folded to form an arched structure. Then, the composite ionomer gel prepared in Example 2 and silicone rubber were respectively glued to the top and bottom of the inner side of the arched structure to prepare a self-powered pressure sensor that exhibits resilience under downward pressure. The output signal was measured using an electrometer within the pressure range of 0.43–5.21 kPa, and the relationship between the output voltage and the corresponding pressure was plotted. The sensitivity and linearity of the pressure sensor were calculated.

[0146] The results are as follows Figure 6 As shown, the sensor constructed from multifunctional composite ionogels exhibits excellent pressure sensing performance, with a sensitivity of 5.890 V kPa in the pressure range of 0.43–2.12 kPa. -1 .

[0147] 3) Motion monitoring

[0148] The self-powered pressure sensor prepared in step 2) was attached to joints such as fingers, wrists and knees, and the output signal of the sensor at different bending angles was measured using an electrometer.

[0149] The results are as follows Figure 7 As shown, when joints such as fingers and wrists are not bent, the sensor does not output a significant signal. However, when bent at a certain angle, the pressure sensors in these areas will contact and separate during the cyclical movement of bending and returning, thereby generating an electrical signal. This indicates that the self-powered pressure sensor can monitor human movement, demonstrating its potential applications in wearable devices and health monitoring.

[0150] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a multifunctional composite ion gel, characterized in that, By weight, 5 parts of polyvinylidene fluoride-hexafluoropropylene copolymer and 1-4 parts of fluorine-containing hydrophobic ionic liquid are added to 0.05-0.5 parts of filler solution and mixed well. Then, 0.15 parts of crosslinking agent are added to react and dried to obtain multifunctional composite ionic gel. The filler is poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, multi-walled carbon nanotubes, or conductive carbon black.

2. The method for preparing the multifunctional composite ion gel according to claim 1, characterized in that, The method for preparing the filler solution is as follows: 0.05 to 0.5 parts of filler are added to 100 parts of solvent and stirred for 12 hours, then ultrasonically dispersed to obtain the filler dispersion. The solvent is N,N-dimethylformamide, dimethyl sulfoxide, or N,N-dimethylacetamide.

3. The method for preparing the multifunctional composite ion gel according to claim 1, characterized in that, The fluorinated hydrophobic ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium hexafluorophosphate, or 1-aminoethyl-3-methylimidazolium hexafluorophosphate.

4. The multifunctional composite ion gel prepared by the preparation method according to any one of claims 1 to 3.

5. The multifunctional composite ion gel according to claim 4, characterized in that, The shape fixation rate and shape recovery rate of the multifunctional composite ion gel are both greater than 98%.

6. A strain sensor, characterized in that, It includes the multifunctional composite ion gel as described in claim 4 or 5.

7. A triboelectric nanogenerator, characterized in that, The multifunctional composite ion gel described in claim 4 or 5 can be used as both a conductive layer and a negative friction layer material.

8. A self-powered pressure sensor, characterized in that, Including the triboelectric nanogenerator as described in claim 7.

9. A self-powered pressure sensor according to claim 8, characterized in that, The self-powered pressure sensor has a sensitivity of 5.890 V kPa in the pressure range of 0.43–2.12 kPa. -1 The self-powered pressure sensor uses a multifunctional composite ion gel made from 0.25 parts poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, 5 parts polyvinylidene fluoride-hexafluoropropylene copolymer, 2 parts ion liquid and 0.15 parts trimethylhexanediamine.

10. The application of the multifunctional composite ion gel of claim 4 or 5, the strain sensor of claim 6, the triboelectric nanogenerator of claim 7, and the self-powered pressure sensor of claim 8 or 9 in the fabrication of multifunctional devices.

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