A method for preparing and applying a photoelectric dual-output photonic crystal ion gel

Abstract

This invention discloses a method for preparing and applying a photonic crystal ion gel with dual photoelectric output. First, Fe3O4@PSSMA@SiO2 nanoparticles are synthesized via a hydrothermal method and mixed in water. A monomer, ionic liquid, crosslinking agent, and initiator are added, and after dissolution, a gel precursor solution is obtained. The gel precursor solution is transferred to a mold, which is then placed in a magnetic field environment and heated. Under the influence of the magnetic field, the magnetic nanoparticles exhibit color development in the ion gel precursor solution, while the gel precursor solution simultaneously undergoes a heating, curing, and crosslinking reaction, thus obtaining the photonic crystal ion gel. This invention fixes the photonic crystal in the form of a one-dimensional chain within a highly conductive ion gel under the influence of a magnetic field. Through thermally initiated polymerization, the prepared ion gel displays a brightly colored structure with a structural color unaffected by angle, and exhibits both mechanochromatic coloration and photoelectric dual response to electrical signal changes. It also possesses good tensile strength, toughness, freeze resistance, and adhesion.

Description

Technical Field

[0001] This invention relates to a method for preparing and applying an ion gel, and more particularly to a method for preparing and applying a photoelectric dual-output photonic crystal ion gel. Background Technology

[0002] Ionogels, composed of ionic liquids and a supporting network, possess numerous superior properties, including high sensitivity, high mechanical strength, excellent adhesion, and ultra-high ionic conductivity. These characteristics have led to their widespread application in many emerging fields such as flexible sensors, ionic skin, and wearable electronic devices. Due to the high flexibility and sensitivity requirements of wearable devices, reading their response behavior typically requires complex instruments, which are often expensive and inconvenient to carry. Therefore, acquiring the intuitive visual color response signals of wearable devices through touch is a novel strategy.

[0003] In nature, visual signals serve as information carriers for biological communication. For example, peacocks use their colorful tail feathers to attract mates. The vibrant colors on peacock feathers are called structural colors, which possess strong stability and durability. These specific colors are produced due to the presence of photonic crystal structures within the organism. Colloidal photonic crystals are periodic structures formed by the arrangement of micron-sized colloidal particles. They exhibit characteristics such as photonic bandgap effects and structural color. When the periodic structure changes under external stimuli, its structural color also changes, generating a visual response to mechanical strain. Therefore, incorporating photonic crystals into ionogels can produce mechanochromic photonic crystal ionogels. By combining the structural color of an elastomer with the ionic conductivity, these gels can serve as flexible strain sensors, simultaneously displaying both light and electrical outputs, and hold great potential in the field of iontophoresis.

[0004] Currently, in addition to mechanochromic hydrogels, there are also reports on electrochromic, photochromic, and thermochromic hydrogel materials. For example, electrochromic ionic gels exhibit excellent physicochemical stability, high color contrast, fast response time, and good durability over thousands of switching cycles (W. Poh, A. Eh, W. Wu, et al., Rapidly Photocurable Solid-State Poly(ionic liquid) Ionogels For Thermally Robust and Flexible Electrochromic Devices, 34(2022)2206952.); photochromic nanocomposite organic hydrogels possess excellent mechanical properties, low-temperature resistance, photochromic properties, and UV blocking properties (J. Chen, T. Sun, et al., Tough, Transparent, and Anti-Freezing Nanocomposite Organohydrogels with Photochromic Properties, 13(2021)31180); thermochromic hydrogels exhibit rapid response and good mechanical properties, with colors switching between two modes at specific temperatures (T. Wu, T. Yin, X. Hu, et al., A Thermochromic Hydrogel for Camouflage and Soft). Display, 8(2020)2000031, etc. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a method for preparing a photoelectric dual-output photoelectric crystal ion gel that not only has a structural color independent of the angle of the photoelectric crystal, but also has a photoelectric dual response of mechanochromatic color and electrical signal change;

[0006] The second objective of this invention is to provide the application of the photoelectric dual-output photonic crystal ion gel obtained by the above method in a wearable sensor for detecting human motion.

[0007] Technical solution: The preparation method of the photoelectric dual-output photonic crystal ion gel of the present invention includes the following steps:

[0008] (1) Fe3O4@PSSMA@SiO2 nanoparticles were synthesized by hydrothermal method;

[0009] (2) Fe3O4@PSSMA@SiO2 nanoparticles were mixed in water, and monomers, ionic liquids, crosslinking agents and initiators were added. After being fully dissolved, a gel precursor solution was obtained.

[0010] (3) The obtained gel precursor liquid is transferred to the mold, the mold is placed in a magnetic field environment and heated; under the action of the magnetic field, the magnetic nanoparticles are colored in the ion gel precursor liquid, and the gel precursor liquid undergoes a heating, curing and cross-linking reaction to obtain a photoelectric dual-output photonic crystal ion gel.

[0011] The specific process of step (1) is as follows: iron salt is dissolved in ethylene glycol, sodium acetate is added, and while stirring, sodium poly(4-styrenesulfonic acid-copoly-maleic acid) salt, L-ascorbic acid and deionized water are added in sequence, followed by sodium hydroxide to carry out a solvothermal reaction; after the reaction is completed, magnetic separation is carried out, the separated product is washed, and then dispersed in deionized water to obtain Fe3O4@PSSMA nanoparticle aqueous solution;

[0012] An aqueous solution of Fe3O4@PSSMA nanoparticles was mixed with anhydrous ethanol and ammonium hydroxide, stirred and heated, and tetraethyl silicate was added at intervals to carry out the reaction. After the reaction, the product was separated by a magnet to obtain Fe3O4@PSSMA@SiO2 colloid, which was then washed to obtain Fe3O4@PSSMA@SiO2 core-shell colloidal nanoparticles.

[0013] In step (1), the mass ratio of ethylene glycol, iron salt, sodium acetate, sodium poly(4-styrenesulfonic acid-copolymer-maleic acid), L-ascorbic acid, deionized water and sodium hydroxide is 17.8:0.26:1.2:0.4:0.0045:0.02~0.05:0.24.

[0014] In step (1), the mass ratio of Fe3O4@PSSMA nanoparticle aqueous solution, anhydrous ethanol, and ammonium hydroxide is 3:15.8:0.86~0.96.

[0015] In step (1), the amount of tetraethyl silicate added each time is 0.687 to 4.122:0.26. The particle size of Fe3O4@PSSMA@SiO2 nanoparticles is controlled by controlling the amount of tetraethyl silicate added.

[0016] In step (1), the solvothermal reaction temperature is 190-200℃ and the heating time is 9-10h.

[0017] The specific process of step (2) is as follows: the monomers acrylamide, N-vinylpyrrolidone, carboxymethyl chitosan, crosslinking agent N,N'-methylenebisacrylamide, thermal initiator ammonium persulfate and Fe3O4@PSSMA@SiO2 colloidal nanoparticles are mixed and dissolved in a mixed solution of ionic liquid 1-ethyl-3-methylimidazolium sulfate and deionized water. After dissolution, a catalyst is added, and a gel precursor solution is obtained by thermally initiated free radical polymerization.

[0018] In step (2), the mass ratio of acrylamide, N-vinylpyrrolidone, carboxymethyl chitosan, deionized water, N,N'-methylenebisacrylamide, ammonium persulfate, and tetramethylethylenediamine is 21.3–36:18.7–33.4:25:60:0.1:0.08:0.4.

[0019] In step (2), the mass ratio of acrylamide to Fe3O4@PSSMA@SiO2 is 3.1:0.01 to 0.02; the mass ratio of acrylamide to 1-ethyl-3-methylimidazolium sulfate is 1:0 to 0.3.

[0020] The specific process of step (3) is as follows: pour the gel precursor solution into the polytetrafluoroethylene mold, place the polytetrafluoroethylene mold on or around the magnet, heat the mold and precursor solution with a heat source to initiate the polymerization reaction, remove the heat source, rely on the heat released by the polymerization reaction to initiate the unreacted area, until the solution in the mold is completely converted into gel, and finally fix the magnetic photonic crystal structure in the gel network to obtain a photonic crystal ion gel with photoelectric dual output under strain stimulation.

[0021] In step (3), the magnetic field strength of the magnet is 5000-8000 Gs.

[0022] In step (3), the heating process raises the thermal initiation temperature to 50-60°C.

[0023] The above method yields a photoelectric dual-output photonic crystal ion gel for use in wearable sensors that detect human motion.

[0024] Invention Principle: This invention proposes a simple method for preparing multifunctional photonic dual-output photonic crystal ion gels using a mixture of acrylamide, N-vinylpyrrolidone, carboxymethyl chitosan, ionic liquid 1-ethyl-3-methylimidazolium sulfate (EMIES), water, N,N'-methylenebisacrylamide, ammonium persulfate, and tetramethylethylenediamine as a gel precursor solution, combined with magnetically assembled Fe3O4@PSSMA@SiO2 colloidal nanoparticles (CNs). The method involves rapid magnetic induction assembly of Fe3O4@PSSMA@SiO2 colloidal nanoparticles (CNs) in the ion gel precursor solution, embedding one-dimensional CPC chain structures within the ion gel framework, successfully preparing a solid cross-linked colored ion gel with PBG properties. The photonic crystal ion gel prepared by this method exhibits good toughness, excellent freeze resistance, and adhesion. Because the ion gel possesses angle-independent structural color, it demonstrates a synchronous electrical and visual response to mechanical strain stimuli during human movement. This rapidly self-assembling PC hydrogel can be used as a multi-signal device and has great potential in human motion recording applications in the field of smart wearable sensors.

[0025] Beneficial effects: Compared with the prior art, the present invention achieves the following significant effects:

[0026] (1) The method of this invention fixes the photonic crystal in the form of a one-dimensional chain in an ion gel with good conductivity under the action of a magnetic field. The ion gel prepared by thermally initiated polymerization exhibits a bright color structure that is not affected by angle. It also has a dual photoelectric response of mechanochromatic color change and electrical signal change. It has good tensile strength, toughness, freeze resistance, and adhesion, and can work normally in low-temperature environments. (2) This invention crosslinks and polymerizes NVP and AAM, which significantly improves the extensibility and toughness of the gel. In addition, the addition of ionic liquid improves the conductivity, freeze resistance and tensile strength of the gel, and the introduction of chitosan gives the gel adhesion. (3) The method of this invention is simple and has low energy consumption. The photoelectric dual-output photonic crystal ion gel can be prepared in one step in a short time through magnetic assembly and thermally initiated polymerization. Mechanical strain stimulation of the gel will cause its color to change, and its resistance will also change synchronously, exhibiting synchronous electrical and visual responses. Attached Figure Description

[0027] Figure 1 The stress-strain curves (a) and the elongation at break and Young's modulus (b) of the photonic crystal ion gel materials prepared in Examples 1-5 at room temperature;

[0028] Figure 2 Photographs of the photonic crystal ion gel columns prepared in Examples 6 and 7 and their color changes as pressure increases;

[0029] Figure 3 Photographs of the circular photonic crystal ion gel film prepared in Example 3 under mechanical bending and microtouch stimulation;

[0030] Figure 4 DSC measurements of the photonic crystal ion gel materials prepared in Examples 1-5 (a) and images of torsion, stretching and bending after freezing at -20°C overnight (b);

[0031] Figure 5 The graph shows the changes in the structural color of the ion gel and the brightness of the LED bulb during a 50% strain stretching cycle, as well as the changes in the photoelectric dual-output photonic crystal ion gel prepared in Example 3.

[0032] Figure 6 The reflection spectrum of the photoelectric dual-output photonic crystal ion gel prepared in Example 3 under tensile strain of 0% to 50% is shown.

[0033] Figure 7 The sensitivity diagram of the photoelectric dual-output photonic crystal ion gel prepared in Example 3 under strain of 0% to 250% is shown.

[0034] Figure 8 Comparison of relative resistance changes of the photonic crystal ion gel prepared in Example 3 under large strains ranging from 40% to 200%;

[0035] Figure 9 The resistance change graph of the photonic crystal ion gel prepared in Example 3 after 500 cycles of repeated loading and unloading at 50% tensile strain. Detailed Implementation

[0036] The present invention will now be described in further detail.

[0037] Example 1

[0038] (1) Dissolve 0.52g of ferric chloride (FeCl3) in 35.6g of ethylene glycol (EG), sonicate for 5 minutes, then add 2.4g of sodium acetate (CH3COONa) and stir magnetically. While stirring, add 0.8g of sodium poly(4-styrenesulfonic acid-copoly-maleic acid) (PSSMA), 0.009g of L-ascorbic acid (vitamin C, AA), and 0.6g of deionized water (H2O) sequentially. After stirring for 1 hour, add 0.48g of sodium hydroxide (NaOH) while stirring and stir magnetically for 3 hours. Transfer to a reaction vessel, heat to react, and after the reaction vessel cools, separate by magnetization. Wash five times with a 1:1 ethanol / water mixture and deionized water, and finally disperse in 25g of deionized water to obtain an aqueous solution of Fe3O4@PSSMA nanoparticles.

[0039] (2) The aqueous solution of 6g Fe3O4@PSSMA nanoparticles prepared in (1) was mixed with 31.6g anhydrous ethanol (C2H5OH) and 1.82g ammonium hydroxide (NH4OH) and sonicated for 5 minutes. Then the mixture was transferred to a 250ml three-necked flask. After stirring at 520rpm for 10 minutes in a 50℃ water bath, 200ul tetraethyl silicate (TEOS) was slowly added every 20 minutes for 3 consecutive times. After stirring for 2 hours, the Fe3O4@PSSMA@SiO2 colloid was separated by a magnet and washed 3 times with ethanol and water to finally obtain Fe3O4@PSSMA@SiO2 core-shell colloidal nanoparticles.

[0040] (3) Preparation by thermally initiated free radical polymerization: First, 3.072g acrylamide (AAM), 2.197g N-vinylpyrrolidone (NVP), 0.25g chitosan (CMC), 0.01g crosslinking agent N,N'-methylenebisacrylamide (MBAA), 0.008g thermal initiator ammonium persulfate (APS) and 0.015g Fe3O4@PSSMA@SiO2 colloidal nanoparticles obtained in step (2) were mixed and dissolved in 6g deionized water. After ultrasonic dissolution, 0.04g catalyst tetramethylethylenediamine (TEMED) was added and fully dissolved and mixed to obtain a gel precursor solution.

[0041] (4) Pour the obtained gel precursor solution into a polytetrafluoroethylene mold, then place the mold on top of a 5000Gs magnet and heat it at 50°C for 3 minutes to solidify it. The product prepared in this example is a photonic crystal ion gel AAM-NVP-EM0 with dual photoelectric output.

[0042] Example 2

[0043] The preparation method in this embodiment is the same as in embodiment 1, except that in step (3), the mass of the solvent deionized water and the ionic liquid are 5.76 g and 0.24 g, respectively, and the mass fraction of the ionic liquid is 2%. The product obtained in this embodiment is a photonic crystal ion gel AAM-NVP-EM2 with dual photoelectric output.

[0044] Example 3

[0045] The preparation method in this embodiment is the same as in embodiment 1, except that in step (3), the mass of the solvent deionized water and the ionic liquid are 5.52 g and 0.48 g, respectively, and the mass fraction of the ionic liquid is 4%. The product obtained in this embodiment is a photonic crystal ion gel AAM-NVP-EM4 with dual photoelectric output.

[0046] Example 4

[0047] The preparation method in this embodiment is the same as in embodiment 1, except that in step (3), the mass of the solvent deionized water and the ionic liquid are 5.30 g and 0.7 g, respectively, and the mass fraction of the ionic liquid is 6%. The product obtained in this embodiment is a photonic crystal ion gel AAM-NVP-EM6 with dual photoelectric output.

[0048] Example 5

[0049] The preparation method in this embodiment is the same as in embodiment 1, except that in step (3), the mass of the solvent deionized water and the ionic liquid are 5.06 g and 0.94 g, respectively, and the mass fraction of the ionic liquid is 8%. The product obtained in this embodiment is a photonic crystal ion gel AAM-NVP-EM8 with dual photoelectric output.

[0050] Example 6

[0051] The preparation method in this embodiment is the same as in embodiment 3, except that the gel precursor solution obtained in step (3) is poured into a test tube, the test tube is placed on one side of a 5000GS magnet and perpendicular to the table, and heated with a 50°C heat source for 3 minutes to solidify it. The product prepared in this embodiment is a green photonic dual-output photonic crystal ion gel column.

[0052] Example 7

[0053] The preparation method of this embodiment is the same as that of embodiment 6, except that in step (1), only 200 μL of tetraethyl orthosilicate (TEOS) is added. The product prepared in this embodiment is a purple photonic crystal ion gel column with dual output photonic photonics.

[0054] Comparative Example 1

[0055] The preparation method of this comparative example is the same as that of Example 1, except that in step (3), the mass of the solvent deionized water and the ionic liquid are 4.82 g and 1.18 g, respectively, and the mass fraction of the ionic liquid is 10%. In step (3), the hydrogel precursor solution did not completely dissolve after 2 hours of sonication, and there was a small amount of polymerization. 0.04 g of the catalyst tetramethylethylenediamine (TEMED) was added, and the resulting gel precursor solution was poured into a polytetrafluoroethylene mold and placed above a magnet. It was then heated at 50°C for 3 minutes to solidify it. The resulting ionic gel was dull in color and uneven in color. This indicates that excessive ionic liquid leads to incomplete dissolution and affects the color development of the photonic crystal in the ionic gel.

[0056] Characterization and performance testing of the products prepared in each example:

[0057] Tensile tests on ionogels were conducted at room temperature using a universal testing machine with a 1000N sensor (Instron 3367, USA). The crosshead tensile speed was 20 mm / min, and the standard strip was 4 mm wide, 1.5 mm thick, and 30 mm long. At least five parallel tests were performed.

[0058] Figure 1 The stress-strain curves (a) and elongation at break and Young's modulus (b) of the photonic crystal ionogel materials prepared in Examples 1-5 are shown. Figure 1 In (b) of the diagram, bar 1 represents the left ordinate, and bar 2 represents the right ordinate. Figure 1 As shown in (a) and (b), when the mass fraction of EMIES added to the AAM-NVP-EM ionomer gel ranged from 0 wt% to 8 wt%, the elongation at break of the material increased from 1231% to 1790%, while the Young's modulus decreased from 31.4 kPa to 14.2 kPa. With increasing EMIES content, the elongation at break of the AAM-NVP-EM ionomer gel increased significantly. However, there was a trade-off between elongation at break and mechanical strength. When the EMIES content was 8%, the AAM-NVP-EM ionomer gel exhibited the highest elongation at break but lower mechanical strength. Therefore, an EMIES content of 4 wt% was selected as the optimal composition.

[0059] Figure 2 These are the green and purple dual-output photonic crystal ion gel columns prepared in Examples 6 and 7, wherein... Figure 2 (a) in the examples is Example 6, and (b) is Example 7. From... Figure 2 As can be seen, the photonic crystal ion gel columns exhibit a distinct redshift in structural color with increasing pressure. Under increasing pressure, the green ion gel column changes color from green to dark red, and returns to its original green color as the pressure is released; correspondingly, the blue ion gel column changes color from blue to orange, and returns to its original blue color after the pressure is released. In Examples 1-5, the mold containing the gel precursor solution was placed horizontally on top of a horizontally placed magnet and heated to polymerize, resulting in strip-shaped photonic crystal ion gels. In Examples 6 and 7, test tubes containing the gel precursor solution were placed on one side of the magnet and perpendicular to the table, and heated to polymerize, resulting in columnar photonic crystal ion gels.

[0060] Figure 3The green circular photonic crystal ionogel film prepared in Example 3 was transferred onto black cardstock. When the surface of the green circular film was compressed due to bending, the central part of the film turned orange; while when the surface was stretched by bending, the entire surface turned pale purple. An instantaneous color response can be observed at localized points where mechanical stimulation is applied. A slight touch on the edge of the green circular film with tweezers results in a noticeable localized color change.

[0061] The low-temperature resistance of the photonic crystal ion gel with dual photoelectric output was evaluated using a differential scanning calorimeter (DSC, 204F1, Netzsch Co., Germany). The scan rate and temperature range were 2 °C / min. -1 Temperatures range from -65℃ to 20℃. All tests were conducted under an N2 atmosphere.

[0062] Figure 4 These are the DSC curves of the photonic crystal ion gel materials prepared in Examples 1-4. From... Figure 4 The DSC curve in (a) shows that when the EMIES content is 0%, there is a peak at -39℃, indicating that the hydrogel without EMIES molecules freezes at around -39℃. When the EMIES content is 2wt%, 4wt%, and 6wt%, the photonic crystal ion gel does not show any heat flow curve peaks in the temperature range of -60℃ to 20℃. This result indicates that the ionic liquid EMIES molecules can form a large number of hydrogen bonds with water, affecting water crystallization, lowering the freezing point of the hydrogel, and that the addition of EMIES lowers the freezing point of water, thus improving the low-temperature resistance of the photonic crystal ion gel. Figure 4 In (b) of the study, the photonic crystal ion gel was placed in a freezer at -25°C for 24 hours. The sample did not freeze, retained high elasticity, and could withstand various deformations such as torsion, tension, and bending without damage, indicating excellent antifreeze behavior at sub-zero temperatures. Its mechanical properties were not affected by the ambient temperature. Furthermore, the structural color of the photonic crystal ion gel remained unchanged during deformation, indicating that low temperatures do not affect its structural color.

[0063] The electrical signals of the photonic crystal ionogel were measured using a digital bridge (TH2830). The strain and pressure sensing properties of the gel under tension were evaluated by placing the sample on the digital bridge and by performing tensile tests using a universal testing machine.

[0064] Figure 5 This demonstrates the structural color changes of the photonic crystal ion gel prepared in Example 3 during a 50% strain tensile cycle, as well as the changes in LED bulb brightness, sensitivity, and stability of the electrical signal output. The photonic crystal ion gel, LED bulb, and power supply are connected in series in the circuit. Figure 5As can be observed, the light bulb in the circuit lights up, indicating that the photonic crystal ion gel is conductive.

[0065] Figure 6 The changes in the reflectance spectrum of the photonic crystal ionomer were demonstrated during stretching from 0% to 50%. As the deformation of the photonic crystal ionomer increased, its color shifted blue, and the bulb dimmed. Subsequently, as the deformation decreased, the color shifted red, and the bulb brightened again. This indicates that mechanical strain stimulation of the photonic crystal ionomer elicits synchronized electrical and visual responses.

[0066] Figure 7 The results demonstrate that the resistivity of the photonic crystal ionogel prepared in Example 3 gradually increases with strain from 0% to 250%, achieving a linearity of 0.982. During stretching, the hydrogel strip gradually elongates, leading to an increase in conductive path length and resistance. The sensitivity of the ionogel is a key consideration for strain detection capability, and it was quantified using the gauge factor (GF). The GF value of this conductive hydrogel reached 0.837.

[0067] Figure 8 As can be observed, the photonic crystal ion gel prepared in Example 3 has a relatively stable ΔR / R0 within the strain range of 40% to 200%, and ΔR / R0 increases with the increase of deformation, exhibiting an arithmetic progression.

[0068] Figure 9 The photonic crystal ionogel prepared in Example 3 underwent 500 cycles of tensile testing under a small strain of 50%. Except for a slight deviation from the baseline, all other data were comparable, and the amplitude and waveform showed no significant differences within the 500 cycles, indicating the excellent stability of the photonic crystal ionogel. These properties confirm the high potential application value of the photoelectric dual-output photonic crystal ionogel prepared in this invention as a wearable sensor for monitoring human motion.

Claims

1. A method for preparing opto-electric dual output photonic crystal ionogel, characterized in that, The method comprises the following steps: (1) synthesizing Fe3O4@PSSMA@SiO2 nanoparticles by a hydrothermal method; (2) mixing the Fe3O4@PSSMA@SiO2 nanoparticles in water, adding monomers, ionic liquid, crosslinking agent and initiator, and obtaining a gel precursor solution after fully dissolving; The specific process of step (2) is as follows: the monomers acrylamide, N-vinyl pyrrolidone, carboxymethyl chitosan, crosslinking agent N,N'-methylene bisacrylamide, thermal initiator ammonium persulfate and Fe3O4@PSSMA@SiO2 colloidal nanoparticles are mixed and dissolved in a mixed solution of ionic liquid 1-ethyl-3-methyl imidazole ethyl sulfate and deionized water, a catalyst is added after dissolution, and a gel precursor solution is obtained by a thermal initiation free radical polymerization method; The mass ratio of acrylamide, N-vinyl pyrrolidone, carboxymethyl chitosan, deionized water, N,N'-methylene bisacrylamide, ammonium persulfate and tetramethyl ethylenediamine is 21.3-36:18.7-33.4:25:60:0.1:0.08:0.4; the mass ratio of acrylamide and Fe3O4@PSSMA@SiO2 is 3.1:0.01-0.02; and the mass ratio of acrylamide and 1-ethyl-3-methyl imidazole ethyl sulfate is 1:0-0.3, wherein 0 is not included; (3) transferring the obtained gel precursor solution to a mold, placing the mold in a magnetic field environment, and heating the mold; under the action of the magnetic field, the magnetic nanoparticles develop color in the ionic gel precursor solution, the gel precursor solution simultaneously undergoes a heating solidification crosslinking reaction, and a photoelectric dual-output photonic crystal ionic gel is prepared.

2. The method of claim 1, wherein the photoelectric dual output photonic crystal ionogel is prepared by the steps of: The specific process of step (1) is as follows: dissolving a ferric salt in ethylene glycol, adding sodium acetate, and adding poly(4-styrene sulfonic acid-co-maleic acid) sodium salt, L-ascorbic acid and deionized water in sequence while stirring, then adding sodium hydroxide, and performing a solvothermal reaction; after the reaction is completed, magnetic separation is performed, the separated product is washed, and then dispersed in deionized water to obtain a Fe3O4@PSSMA nanoparticle aqueous solution; The Fe3O4@PSSMA nanoparticle aqueous solution, anhydrous ethanol and ammonia hydroxide are mixed, heated and stirred, and tetraethyl silicate is added at intervals to perform a reaction; after the reaction, the product is separated by a magnet to obtain Fe3O4@PSSMA@SiO2 colloid, and Fe3O4@PSSMA@SiO2 core-shell colloidal nanoparticles are obtained after washing.

3. The method of claim 1, wherein the photoelectric dual output photonic crystal ionogel is prepared by the steps of: The specific process of step (3) is as follows: pouring the gel precursor solution into a polytetrafluoroethylene mold, placing the polytetrafluoroethylene mold on or around a magnet, heating the mold and the precursor solution by a heat source to initiate a polymerization reaction, removing the heat source, relying on the heat released by the polymerization reaction to initiate the unreacted area, until the solution in the mold is completely converted into a gel, and finally fixing the magnetic photonic crystal structure in the gel network to prepare a photoelectric dual-output photonic crystal ionic gel under strain stimulation.

4. The method for preparing optoelectronic dual output photonic crystal ionogel according to claim 1, characterized in that, In step (3), the magnetic field strength is 5000-8000Gs.

5. The method for preparing optoelectronic dual output photonic crystal ionogel as claimed in claim 1, wherein, In step (3), the heating makes the thermal initiation temperature 50-60℃.

6. The method for preparing optoelectronic dual output photonic crystal ionogel as claimed in claim 2, wherein, In step (1), the mass ratio of the ethylene glycol, iron salt, sodium acetate, poly(4-styrene sulfonic acid-co-maleic acid) sodium salt, L-ascorbic acid, deionized water and sodium hydroxide is 17.8:0.26:1.2:0.4:0.0045:0.02~0.05:0.24; the mass ratio of the Fe3O4@PSSMA nanoparticle aqueous solution, anhydrous ethanol and ammonium hydroxide is 3:15.8:0.86~0.96; the mass ratio of the tetraethyl silicate and iron salt added each time is 0.687~4.122:0.26, and the particle size of the Fe3O4@PSSMA@SiO2 nanoparticle is regulated by controlling the addition amount of the tetraethyl silicate.

7. The method for preparing optoelectronic dual output photonic crystal ionogel as claimed in claim 2, wherein, In step (1), the solvent thermal reaction temperature is 190~200℃, and the heating time is 9~10h.

8. Application of the photoelectric dual-output photonic crystal ionic gel obtained by the method in claim 1 in a wearable sensor for detecting human motion.

Images