Self-adhesion anti-water-loss gelatin ionic gel with high ionic conductivity as well as preparation method and application of self-adhesion anti-water-loss gelatin ionic gel

Abstract

The invention discloses self-adhesion anti-water-loss gelatin ionic gel with high ionic conductivity as well as a preparation method and application of the self-adhesion anti-water-loss gelatin ionic gel, and belongs to the technical field of polymer ionic gel. The self-adhesion anti-water-loss gelatin ionic gel with high ionic conductivity is prepared from gelatin and a non-aqueous solvent, wherein the non-aqueous solvent is a choline chloride-sodium pyrrolidone carboxylate non-aqueous solvent or a betaine-sodium pyrrolidone carboxylate non-aqueous solvent. In the preparation process, water is not added as a solvent, water loss is not likely to happen in the use process, and the stability of mechanical performance and electrical performance is easy to maintain; the gelatin ionic gel prepared by the invention has the characteristics of water loss resistance, self-adhesion, reusability, ionic conductivity, in-situ polymerization, patterning and the like, can conformally form gel on the surface of skin through an in-situ polymerization method, and has the advantages of high skin adaptability, good stretchability, high sensitivity, capability of being directly written by ink for patterning and the like.

Description

Technical Field

[0001] This invention belongs to the field of polymer ionogel technology, and more specifically, relates to a self-adhesive gelatin ionogel with high ionic conductivity and resistance to water loss, as well as its preparation method and application. Background Technology

[0002] In recent years, with the rapid development of wearable devices and biomedical sensors, higher requirements have been placed on flexible, biocompatible physiological signal electrodes. These electrodes need to have good biocompatibility, conductivity, and mechanical flexibility, while also being able to operate stably for a long time.

[0003] However, traditional gel materials often suffer from problems such as easy water loss, poor adhesion, and difficulty in regeneration, resulting in poor long-term electrode performance. Furthermore, achieving in-situ polymerization and patterning of materials to meet the application requirements of conformally attaching electrodes (or sensors) on the complex surfaces of human skin is also a significant challenge. Therefore, developing a flexible gel material that combines resistance to water loss, self-adhesion, regeneration, ionic conductivity, in-situ polymerization, and patternability is crucial for realizing high-performance electrophysiological signal electrodes.

[0004] Chinese patent CN 116284863 A discloses a method for preparing an anti-dehydration ion-conductive gelatin hydrogel. The specific preparation method involves: soaking gelatin in deionized water to swell, then magnetically stirring it in a water bath to obtain a gelatin solution; adding sodium pyrrolidone carboxylate to the gelatin solution to obtain a gelatin-sodium pyrrolidone carboxylate mixed solution; and cooling the gelatin-sodium pyrrolidone carboxylate mixed solution at a certain temperature to obtain a gelatin-sodium pyrrolidone carboxylate hydrogel. The prepared gelatin-sodium pyrrolidone carboxylate hydrogel contains a high water content and will experience dehydration; furthermore, the gelatin-sodium pyrrolidone carboxylate hydrogel has a curing temperature of 10-20 degrees Celsius, which is considered low-temperature curing and not suitable for in-situ curing on the skin surface at room temperature.

[0005] Chinese patent CN 112608431 A discloses an ion-conductive hydrogel, its preparation method, and its application. The specific preparation method is as follows: 1) Gelatin, acrylamide, and aldehyde-modified β-cyclodextrin are mixed with water to form a solution, then a crosslinking agent and inorganic salts are added, and the solution is stirred and dissolved to obtain a viscous solution; 2) An initiator and catalyst are added to the viscous solution, which is then poured into a mold and cured to obtain the ion-conductive hydrogel. The prepared ion-conductive hydrogel has a risk of dehydration and may lead to the precipitation of inorganic salts. The gel preparation process requires crosslinking and curing at high temperatures, and gelation cannot be performed in situ on the skin. Furthermore, this high-temperature curing method makes it difficult to pattern.

[0006] Chinese patent CN 116606456 A discloses an ion-conducting gel, its preparation method, and its application. The specific preparation method includes: S1, adding an organic solvent to a precursor solution and stirring to obtain a mixed solution; the precursor solution includes acrylic monomer, gelatin monomer, N-succinimidyl acrylate, α-ketoglutaric acid monomer, methacryloyl gelatin, and glycerol; the organic solvent includes glycerol and water; S2, gelling the mixed solution to obtain an ion-conducting gel; S3, immersing the ion-conducting gel in an ion solution and drying it to obtain the ion-conducting gel. The gel preparation process is complex and requires cross-linking and curing under ultraviolet light, making in-situ gelation on the skin impossible. Furthermore, this high-temperature curing method makes it difficult to pattern. Summary of the Invention

[0007] To address the aforementioned problems in existing technologies, the technical problem this invention aims to solve is to provide a method for preparing a self-adhesive, water-resistant, and highly ionicly conductive gelatin ionomer, which eliminates the need for water as a solvent, minimizes water loss during use, and easily maintains the stability of its mechanical and electrical properties. Another technical problem this invention aims to solve is to provide a self-adhesive, water-resistant, and highly ionicly conductive gelatin ionomer prepared by the above method, which possesses advantages such as high skin compatibility, good stretchability, high sensitivity, and the ability to be directly patterned using ink. Furthermore, this invention also aims to address the application of the above-mentioned self-adhesive, water-resistant, and highly ionicly conductive gelatin ionomer in electrophysiological signal electrodes or as a flexible strain sensor component.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a self-adhesive gelatin ionomer with high ionic conductivity and resistance to water loss involves adding gelatin powder to a non-aqueous solvent to swell, heating and stirring to obtain a transparent gelatin-non-aqueous solvent mixture, and then cooling to obtain a self-adhesive gelatin ionomer with high ionic conductivity and resistance to water loss. The non-aqueous solvent is either choline chloride-pyrrolidone sodium carboxylate or betaine-pyrrolidone sodium carboxylate.

[0010] Preferably, in the non-aqueous solvent, the molar ratio of choline chloride to sodium pyrrolidone carboxylate is 1:1 to 1:3, and the molar ratio of betaine to sodium pyrrolidone carboxylate is 1:2 to 2:1.

[0011] Preferably, a non-aqueous solvent is used as the solvent, and the solid content of the gelatin powder is 10-30 wt%.

[0012] As a preferred method, the specific process is as follows: gelatin powder is added to a non-aqueous solvent, allowed to swell at room temperature, then magnetically stirred in a water bath, and cooled to obtain gelatin ionogel.

[0013] Preferably, the swelling time is 10–60 min, the water bath temperature is 55–80 °C, the magnetic stirring time is 60–120 min, the cooling temperature is 4–30 °C, and the cooling time is 5–120 min.

[0014] The method for preparing the self-adhesive, water-resistant, and highly ionic conductive gelatin ionogel described above yields a gelatin ionogel.

[0015] The gelatin ionogel is composed of gelatin and a non-aqueous solvent; wherein the non-aqueous solvent is either choline chloride-pyrrolidone carboxylate sodium non-aqueous solvent or betaine-pyrrolidone carboxylate sodium non-aqueous solvent.

[0016] The ionic conductivity of the gelatin ionomer is 1–8 mS / cm.

[0017] The application of the gelatin ionogel in electrophysiological signal electrodes.

[0018] The gelatin ionogel is used as a flexible strain sensor component.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0020] 1) The raw materials used in this invention, namely gelatin, betaine, choline chloride and sodium pyrrolidone carboxylate, are all natural biomass or derivatives, which have good biocompatibility, high safety and are green and environmentally friendly; the preparation method is simple and easy to promote.

[0021] 2) In this invention, the introduction of choline chloride / betaine and sodium pyrrolidone carboxylate can form strong hydrogen bonds and electrostatic interactions with gelatin chains, which can significantly improve the mechanical properties of gelatin gel; at the same time, the introduction of sodium ions contributes to the high conductivity of gelatin ion gel.

[0022] 3) The gelatin ionogel prepared by the present invention exhibits reversible fluid-gel transition characteristics under temperature control due to the triple helix structure of gelatin, which enables it to be patterned and gelled in situ on various substrates and skin surfaces, thereby ensuring adhesion and dynamic compliance with curved surfaces.

[0023] 4) The gelatin ionomer of the present invention does not add water as a solvent during the preparation process, and is not prone to water loss during use, thus easily maintaining the stability of mechanical and electrical properties;

[0024] 5) The gelatin ionogel prepared by this invention can be easily heated back into a liquid and then regelled as needed to achieve repeated recycling;

[0025] 6) The gelatin ion gel prepared by this invention has the properties of anti-dehydration, self-adhesion, recyclability, ionic conductivity, in-situ polymerization and patterning. It can be conformally formed on the skin surface by in-situ polymerization and has the advantages of high skin compatibility, good stretchability, high sensitivity and direct ink writing for patterning.

[0026] 7) The gelatin ionogel prepared by the present invention can be directly polymerized in situ on human skin to form a conformal flexible sensor or a conformal physiological signal electrode, so as to detect human physiological signals with high performance or serve as a human-computer interaction interface. Attached Figure Description

[0027] Figure 1 The UV-Vis transmission spectrum of the gelatin ionogel prepared in Example 1;

[0028] Figure 2 Stress-strain diagrams of the gelatin ionomers prepared in Examples 1-5;

[0029] Figure 3 Stress-strain diagrams of the gelatin ionomers prepared in Examples 6-8;

[0030] Figure 4 Stress-strain diagram of the gelatin hydrogel prepared in Comparative Example 1;

[0031] Figure 5 This is a comparison diagram of the skin contact impedance of the gelatin ionomer prepared in Example 1 and the skin contact impedance of a commercial electrocardiogram electrode;

[0032] Figure 6 The image shows the water retention of the gelatin ionogel prepared in Example 1 after being placed under environmental conditions for one month.

[0033] Figure 7 A comparison of electromyographic signals acquired by the gelatin ionogel prepared in Example 1 as an electrophysiological signal electrode and a commercially available electrocardiogram electrode.

[0034] Figure 8 A comparison of electrocardiogram (ECG) signals acquired using the gelatin ionogel prepared in Example 1 as an electrophysiological signal electrode and commercial ECG electrodes.

[0035] Figure 9 A comparison of electroencephalograms (EEGs) with those obtained by gelatin ionogel prepared in Example 1 as electrophysiological signal electrodes and commercially available EEG gels in open / closed eye states.

[0036] Figure 10 The time-spectral diagram of electroencephalogram (EEG) signals acquired in the open / closed state using the gelatin ionogel prepared in Example 1 as an electrophysiological signal electrode.

[0037] Figure 11A comparison of electrooculography signals acquired by the gelatin ionogel prepared in Example 1 as an electrophysiological signal electrode and a commercially available electrocardiogram electrode.

[0038] Figure 12 The image shows the sensing performance test results of the gelatin ionogel-based strain sensor prepared in Example 1.

[0039] Figure 13 This is a patterned image of the gelatin ionogel (dyed with food coloring) prepared in Example 4 on a PET substrate. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is further described below with reference to specific embodiments. Unless otherwise specified, the technical means used in the following embodiments are all conventional means well known to those skilled in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0041] The performance testing method used in this invention is as follows:

[0042] 1. Stress-strain: The stress-strain curve of the gelatin ionogel was tested using a universal testing machine (Instron 3343). The gelatin ionogel was cut into a cuboid with a length of 40 mm, a width of 5 mm, and a thickness of 4 mm. The distance between the clamps of the testing machine was 10 mm, and the tensile rate was 50 mm / min.

[0043] 2. Conductivity: The AC impedance spectrum of gelatin ionomer was tested at room temperature using an electrochemical workstation (Chenhua CHI660E), and the conductivity was calculated using the formula σ=d / RS.

[0044] 3. Sensing performance test: The gelatin ionogel-based sensor was stretched using a universal testing machine, and the resistance change of the sensor was recorded using an LCR meter.

[0045] Example 1

[0046] A method for preparing a self-adhesive gelatin ionogel with high ionic conductivity and resistance to water loss specifically includes the following steps:

[0047] 1) Mix betaine and sodium pyrrolidone carboxylate at a molar ratio of 1:1 and stir until clear and transparent to obtain a non-aqueous solvent of betaine-sodium pyrrolidone carboxylate;

[0048] 2) Take 2.2g of gelatin powder and add it to 7.8g of the non-aqueous solvent of betaine-pyrrolidone sodium carboxylate prepared in step 1). Let it swell at room temperature for 60min to obtain a gelatin swollen mixture.

[0049] 3) Place the gelatin swelling mixture prepared in step 2) in a water bath at 60°C and stir magnetically at 600 rpm for 120 min to obtain a transparent gelatin-non-aqueous solvent mixture solution.

[0050] 4) The transparent gelatin-non-aqueous solvent mixture prepared in step 3) is injected into the mold and cooled at room temperature for 60 minutes to obtain gelatin ionogel.

[0051] The transparent gelatin-non-aqueous solvent mixture prepared in Example 1 was applied to the corresponding position on the human epidermis using a template or ink direct writing pattern, and after cooling at room temperature for 5 minutes, a transparent conformal gel electrode or sensor was formed in situ on the skin surface.

[0052] The gelatin ionogel prepared in Example 1 was cut into 2 mm thick test samples, and its transmittance was tested using a UV-Vis spectrometer. The test results are as follows: Figure 1 As shown.

[0053] Depend on Figure 1 It can be seen that the transmittance of gelatin ionomer is above 80% in the entire visible light region, indicating that gelatin ionomer has high transparency.

[0054] The skin contact impedance of the gelatin ionogel prepared in Example 1 was tested using an impedance analyzer (Hioki IM3570). The test results are as follows: Figure 2 As shown.

[0055] Depend on Figure 2 It can be seen that the skin contact impedance of the gelatin ionomer prepared in Example 1 is 31kΩ (100Hz), which is significantly lower than that of the 242kΩ (100Hz) of commercial ECG electrodes.

[0056] The gelatin ionogel block prepared in Example 1 was placed under environmental conditions (25°C, 60% RH), and its mass change was recorded periodically. The results are as follows: Figure 3 As shown.

[0057] Depend on Figure 3 It can be seen that the gelatin ionogel prepared in Example 1 has good water retention properties.

[0058] Example 2

[0059] A method for preparing a self-adhesive gelatin ionogel with high ionic conductivity and resistance to water loss specifically includes the following steps:

[0060] 1) Mix betaine and sodium pyrrolidone carboxylate at a molar ratio of 1:2 and stir until clear and transparent to obtain a non-aqueous solvent of betaine-sodium pyrrolidone carboxylate;

[0061] 2) Take 2.2g of gelatin powder and add it to 7.8g of the non-aqueous solvent of betaine-pyrrolidone sodium carboxylate prepared in step 1). Let it swell at room temperature for 60min to obtain a gelatin swollen mixture.

[0062] 3) Place the gelatin swelling mixture prepared in step 2) in a water bath at 60°C and stir magnetically at 600 rpm for 120 min to obtain a transparent gelatin-non-aqueous solvent mixture solution.

[0063] 4) The transparent gelatin-non-aqueous solvent mixture prepared in step 3) is injected into the mold and cooled at room temperature for 60 minutes to obtain gelatin ionogel.

[0064] The transparent gelatin-non-aqueous solvent mixture prepared in Example 2 was applied to the corresponding position on the human epidermis using a template or ink direct writing pattern, and after cooling at room temperature for 5 minutes, a transparent conformal gel electrode or sensor was formed in situ on the skin surface.

[0065] Example 3

[0066] A method for preparing a self-adhesive gelatin ionogel with high ionic conductivity and resistance to water loss specifically includes the following steps:

[0067] 1) Mix betaine and sodium pyrrolidone carboxylate at a molar ratio of 2:1 and stir until clear and transparent to obtain a non-aqueous solvent of betaine-sodium pyrrolidone carboxylate;

[0068] 2) Take 2.2g of gelatin powder and add it to 7.8g of the non-aqueous solvent of betaine-pyrrolidone sodium carboxylate prepared in step 1). Let it swell at room temperature for 60min to obtain a gelatin swollen mixture.

[0069] 3) Place the gelatin swelling mixture prepared in step 2) in a water bath at 60°C and stir magnetically at 600 rpm for 120 min to obtain a transparent gelatin-non-aqueous solvent mixture solution.

[0070] 4) The transparent gelatin-non-aqueous solvent mixture prepared in step 3) is injected into the mold and cooled at room temperature for 60 minutes to obtain gelatin ionogel.

[0071] The transparent gelatin-non-aqueous solvent mixture prepared in Example 3 was applied to the corresponding position on the human epidermis using a template or ink direct writing pattern, and after cooling at room temperature for 5 minutes, a transparent conformal gel electrode or sensor was formed in situ on the skin surface.

[0072] Example 4

[0073] A method for preparing a self-adhesive gelatin ionogel with high ionic conductivity and resistance to water loss specifically includes the following steps:

[0074] 1) Mix betaine and sodium pyrrolidone carboxylate at a molar ratio of 1:1 and stir until clear and transparent to obtain a non-aqueous solvent of betaine-sodium pyrrolidone carboxylate;

[0075] 2) Take 1g of gelatin powder and add it to 9g of the non-aqueous solvent of betaine-pyrrolidone sodium carboxylate prepared in step 1). Let it swell at room temperature for 60min to obtain a gelatin swollen mixture.

[0076] 3) Place the gelatin swelling mixture prepared in step 2) in a water bath at 80°C and stir magnetically at 400 rpm for 120 min to obtain a transparent gelatin-non-aqueous solvent mixed solution.

[0077] 4) The transparent gelatin-non-aqueous solvent mixture prepared in step 3) is injected into the mold and cooled at room temperature for 60 minutes to obtain gelatin ionogel.

[0078] The transparent gelatin-non-aqueous solvent mixture prepared in Example 4 was applied to the corresponding position on the human epidermis using a template or ink direct writing pattern, and after cooling at 30°C for 10 min, a transparent conformal gel electrode or sensor was formed in situ on the skin surface.

[0079] Example 5

[0080] A method for preparing a self-adhesive gelatin ionogel with high ionic conductivity and resistance to water loss specifically includes the following steps:

[0081] 1) Mix betaine and sodium pyrrolidone carboxylate at a molar ratio of 1:1 and stir until clear and transparent to obtain a non-aqueous solvent of betaine-sodium pyrrolidone carboxylate;

[0082] 2) Take 3g of gelatin powder and add it to 7g of the non-aqueous solvent of betaine-pyrrolidone sodium carboxylate prepared in step 1). Let it swell at room temperature for 60 minutes to obtain a gelatin swollen mixture.

[0083] 3) Place the gelatin swelling mixture prepared in step 2) in a water bath at 80°C and stir magnetically at 400 rpm for 120 min to obtain a transparent gelatin-non-aqueous solvent mixed solution.

[0084] 4) The transparent gelatin-non-aqueous solvent mixture prepared in step 3) is injected into the mold and cooled at room temperature for 60 minutes to obtain gelatin ionogel.

[0085] The transparent gelatin-non-aqueous solvent mixture prepared in Example 5 was applied to the corresponding position on the human epidermis using a template or ink direct writing pattern, and after cooling at 30°C for 10 min, a transparent conformal gel electrode or sensor was formed in situ on the skin surface.

[0086] Example 6

[0087] A method for preparing a self-adhesive gelatin ionogel with high ionic conductivity and resistance to water loss specifically includes the following steps:

[0088] 1) Mix choline chloride and sodium pyrrolidone carboxylate at a molar ratio of 1:1 and stir until clear and transparent to obtain a choline chloride-sodium pyrrolidone carboxylate mixed solution in a non-aqueous solvent.

[0089] 2) Take 1.6g of gelatin powder and add it to 8.4g of the non-aqueous solvent of the choline chloride-pyrrolidone sodium carboxylate mixed solution prepared in step 1). Let it swell at room temperature for 30min to obtain a gelatin swollen mixture.

[0090] 3) Place the gelatin swelling mixture prepared in step 2) in a water bath at 60°C and stir magnetically at 500 rpm for 60 min to obtain a transparent gelatin-non-aqueous solvent mixed solution.

[0091] 4) The transparent gelatin-non-aqueous solvent mixture prepared in step 3) is injected into the mold and cooled at 4°C for 60 min to obtain gelatin ionogel.

[0092] Example 7

[0093] A method for preparing a self-adhesive gelatin ionogel with high ionic conductivity and resistance to water loss specifically includes the following steps:

[0094] 1) Mix choline chloride and sodium pyrrolidone carboxylate at a molar ratio of 1:2 and stir until clear and transparent to obtain a non-aqueous solvent of choline chloride-sodium pyrrolidone carboxylate.

[0095] 2) Take 1.6g of gelatin powder and add it to 8.4g of the non-aqueous solvent of choline chloride-pyrrolidone sodium carboxylate prepared in step 1). Let it swell at room temperature for 30min to obtain a gelatin swollen mixture.

[0096] 3) Place the gelatin swelling mixture prepared in step 2) in a water bath at 60°C and stir magnetically at 500 rpm for 60 min to obtain a transparent gelatin-non-aqueous solvent mixed solution.

[0097] 4) The transparent gelatin-non-aqueous solvent mixture prepared in step 3) is injected into the mold and cooled at 4°C for 60 min to obtain gelatin ionogel.

[0098] Example 8

[0099] A method for preparing a self-adhesive gelatin ionogel with high ionic conductivity and resistance to water loss specifically includes the following steps:

[0100] 1) Mix choline chloride and sodium pyrrolidone carboxylate at a molar ratio of 1:3 and stir until clear and transparent to obtain a choline chloride-sodium pyrrolidone carboxylate mixed solution that is not an aqueous solvent;

[0101] 2) Take 1.6g of gelatin powder and add it to 8.4g of the non-aqueous solvent of the choline chloride-pyrrolidone sodium carboxylate mixed solution prepared in step 1). Let it swell at room temperature for 30min to obtain a gelatin swollen mixture.

[0102] 3) Place the gelatin swelling mixture prepared in step 2) in a water bath at 60°C and stir magnetically at 500 rpm for 60 min to obtain a transparent gelatin-non-aqueous solvent mixed solution.

[0103] 4) The transparent gelatin-non-aqueous solvent mixture prepared in step 3) is injected into the mold and cooled at 4°C for 60 min to obtain gelatin ionogel.

[0104] Comparative Example 1

[0105] Take 2.2g of gelatin powder, add it to 7.8g of deionized water, let it swell at room temperature for 30min, then place it in a water bath at 60℃ and stir magnetically at 600rpm for 60min to obtain a transparent gelatin aqueous solution; pour the gelatin aqueous solution into a mold and cool it at room temperature for 120min to obtain a gelatin hydrogel.

[0106] The stress-strain and conductivity of the gelatin ionomers prepared in Examples 1-8 and Comparative Example 1 were tested, and the results are as follows: Figure 4-6 As shown in Table 1.

[0107] Table 1. Performance results of gelatin ionogels prepared in Examples 1-8 and Comparative Example 1

[0108] Elongation at break % Fracture stress kPa Conductivity mS / cm Example 1 885 402 3.51 Example 2 642 340 4.71 Example 3 736 427 1.89 Example 4 437 71 7.13 Example 5 772 486 1.31 Example 6 769 20 5.26 Example 7 1163 53 6.52 Example 8 1286 60 6.21 Comparative Example 1 45 12 0.61

[0109] Depend on Figure 4-6 As shown in Table 1, the gelatin ionomers prepared in Examples 1-5 have an elongation at break of 437–885% and a tensile stress of 71–486 kPa. The gelatin ionomers prepared in Examples 6-8 have an elongation at break of 769–1286% and a tensile stress of 20–60 kPa. The gelatin hydrogel prepared in Comparative Example 1 has an elongation at break of 45% and a tensile strength of 12 kPa. The mechanical properties of the gelatin ionomers prepared in this invention are significantly higher than those in Comparative Example 1.

[0110] Example 9

[0111] After mounting metal electrodes and wires on the conformal gel electrode surface of Example 1, it can be used for human physiological signal detection (ECG, EMG, EEG, EOS) and long-term monitoring of human electrophysiological signals. Results are as follows... Figures 7-10 As shown.

[0112] Metal wires were connected to both ends of the conformal gel electrode in Example 1 to fabricate a flexible strain sensor for detecting human motion signals. The results are as follows: Figure 12 As shown.

[0113] Depend on Figure 7 It can be seen that the in-situ conformal gel electrode obtained in Example 1 was successfully used to acquire electromyographic signals.

[0114] Depend on Figure 8 It can be seen that the in-situ conformal gel electrode obtained in Example 1 was successfully used for electrocardiogram signal acquisition.

[0115] Depend on Figure 9 and Figure 10 It can be seen that the in-situ conformal gel electrode obtained in Example 1 was successfully used to acquire alpha waves of EEG signals.

[0116] Depend on Figure 11 It can be seen that the in-situ conformal gel electrode obtained in Example 1 was successfully used to acquire electrooculography signals.

[0117] Depend on Figure 12 It can be seen that the response curves of the relative resistance change ΔR / R0 (where ΔR is the difference between the resistance R0 in the initial state and the resistance R in the tensile state) of the strain sensor prepared using the gelatin ionogel obtained in Example 1 under different strains with respect to the degree of strain show that the sensor has high repeatability under tensile strain of 5%-500%, indicating that it has high response stability.

[0118] Depend on Figure 13 It can be seen that different patterned gels can be obtained by using the gelatin ion gel (food coloring) obtained in Example 4 through template or ink direct writing.

[0119] Example 10

[0120] The gelatin ionomer obtained in Example 1 was heated in a 60-degree oven for 30 minutes to obtain a transparent gelatin-non-aqueous solvent mixture. The transparent gelatin-non-aqueous solvent mixture was injected into a mold again and cooled at room temperature for 60 minutes to obtain a new gelatin ionomer. The transparent gelatin-non-aqueous solvent mixture was patterned on the corresponding position of the human epidermis using a template or ink direct writing and cooled at room temperature for 10 minutes to obtain a transparent conformal gel electrode or sensor formed in situ on the skin surface.

[0121] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a self-adhesive, water-resistant, and highly ionic conductive gelatin ionogel, characterized in that, Gelatin powder was added to a non-aqueous solvent to swell, heated and stirred to obtain a transparent gelatin-non-aqueous solvent mixture. After cooling, a self-adhesive gelatin ionomer gel with high ionic conductivity and resistance to water loss was obtained. The non-aqueous solvent was either choline chloride-pyrrolidone carboxylate or betaine-pyrrolidone carboxylate.

2. The method for preparing the self-adhesive, water-resistant, high ionic conductivity gelatin ionogel according to claim 1, characterized in that, In the non-aqueous solvent, the molar ratio of choline chloride to sodium pyrrolidone carboxylate is 1:1 to 1:3, and the molar ratio of betaine to sodium pyrrolidone carboxylate is 1:2 to 2:

1.

3. The method for preparing the self-adhesive, water-resistant, and high ionic conductivity gelatin ionogel according to claim 1, characterized in that, Using a non-aqueous solvent as the solvent, the solid content of the gelatin powder is 10–30 wt%.

4. The method for preparing the self-adhesive, water-resistant, high ionic conductivity gelatin ionogel according to claim 1, characterized in that, The specific process is as follows: gelatin powder is added to a non-aqueous solvent, allowed to swell at room temperature, then magnetically stirred in a water bath, and cooled to obtain gelatin ionogel.

5. The method for preparing the self-adhesive, water-resistant, high ionic conductivity gelatin ionogel according to claim 4, characterized in that, The swelling time is 10–60 min, the water bath temperature is 55–80 °C, the magnetic stirring time is 60–120 min, the cooling temperature is 4–30 °C, and the cooling time is 5–120 min.

6. The method for preparing the self-adhesive, water-resistant, high ionic conductivity gelatin ionogel according to any one of claims 1 to 5, wherein the gelatin ionogel is prepared.

7. The self-adhesive, water-resistant, high ionic conductivity gelatin ionogel according to claim 6, characterized in that, The gelatin ionogel is composed of gelatin and a non-aqueous solvent; wherein the non-aqueous solvent is either choline chloride-pyrrolidone carboxylate sodium non-aqueous solvent or betaine-pyrrolidone carboxylate sodium non-aqueous solvent.

8. The self-adhesive, water-resistant, high ionic conductivity gelatin ionogel according to claim 6, characterized in that, The ionic conductivity of the gelatin ionomer is 1–8 mS / cm.

9. The application of the gelatin ionogel according to any one of claims 6-8 in electrophysiological signal electrodes.

10. The application of the gelatin ionogel according to any one of claims 6-8 as a flexible strain sensor component.

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