Organic solvent-water dual solvent composite hydrogel and its preparation method and application

Abstract

The present invention belongs to the field of hydrogels and flexible sensing, specifically to an organic solvent-water dual-solvent composite hydrogel, its preparation method, and application. Aminopolysilane and polyvinyl alcohol are dissolved in water and heated for reaction. A polyacid is then added to react to obtain a mixture. The mixture is centrifuged and subjected to freeze-thaw cycles to obtain an organosilicon-reinforced polyvinyl alcohol composite hydrogel. The organosilicon-reinforced polyvinyl alcohol composite hydrogel is then placed in an organic solvent or an aqueous solution of an organic solvent for solvent exchange to obtain an organic solvent-water dual-solvent composite hydrogel.

Description

Technical Field

[0001] The invention belongs to the field of hydrogels and flexible sensors, and particularly relates to an organic solvent-water dual solvent composite hydrogel and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Flexible, extendable, wearable strain sensors that can simultaneously detect external deformation in real time and convert it into electrical signals have attracted widespread attention due to their important applications in electronic skin, soft robotics, human-machine interfaces, and human health monitoring. Strain sensors exhibit changes in elongation and contraction under external forces, generating reproducible electrical signals. However, most strain sensors suffer from limitations such as narrow detection range, low tensile strain, poor durability, and cumbersome fabrication methods.

[0004] Polymer hydrogels are three-dimensional cross-linked networks formed by physical or chemical crosslinking using water as a dispersion medium. They feature simple synthesis techniques and easily adjustable water content. They can maintain structural integrity during deformation and possess flexibility similar to that of biological tissue. Compared to traditional strain sensor materials such as metals and polymers, hydrogels possess superior mechanical properties. However, their vulnerability to dehydration in low-humidity environments and swelling in high-humidity or aqueous environments inhibits their mechanical strength and functionality, limiting their application as strain sensors. Furthermore, while the introduction of conductive fillers such as MXenes, carbon nanotubes, rGO, graphene, polypyrrole, and polyaniline into the hydrogel matrix can improve hydrogel conductivity, the addition of fillers can negatively impact the hydrogel's inherent mechanical properties and strength. Polymer hydrogels still struggle to simultaneously meet the requirements for both mechanical strength and conductivity for wearable strain sensors. Summary of the Invention

[0005] To address the shortcomings of the existing technology, the present invention provides an organic solvent-water dual-solvent composite hydrogel, its preparation method, and applications. The present invention first synthesizes and prepares a tough and conductive organosilicon-reinforced polyvinyl alcohol composite hydrogel. Furthermore, through a solvent replacement strategy, the organic solvent-water dual-solvent composite hydrogel is prepared with significantly enhanced mechanical, water-retention, and electrical properties. This dual-solvent organic solvent-water composite hydrogel can be used as a wearable strain sensor to detect extremely small strains, including those caused by smiling and talking.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing an organic solvent-water dual solvent composite hydrogel, comprising the following steps:

[0008] S1, dissolving aminopolysilane and polyvinyl alcohol in water and heating for reaction, adding polyacid for reaction to obtain a mixture, and centrifuging, freezing, and thawing the mixture to obtain a silicone-reinforced polyvinyl alcohol composite hydrogel;

[0009] S2. placing the organosilicon-reinforced polyvinyl alcohol composite hydrogel in an organic solvent or an aqueous solution of an organic solvent for solvent replacement to obtain an organic solvent-water dual-solvent composite hydrogel.

[0010] Preferably, in step S1, the aminopolysilane is prepared by mixing aminosilane and water, heating and refluxing, removing water in vacuo, and cooling under reduced pressure.

[0011] Further preferably, the aminosilane includes at least one of 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)methyldiethoxysilane and trimethoxy[3-(methylamino)propyl]silane, and the molar ratio of the aminosilane to water is 1:(2 to 5).

[0012] More preferably, the mixture is heated to 140°C to 160°C in a N2 atmosphere and refluxed for 1 to 2 hours, dehydrated under vacuum at 140°C to 160°C for 1 to 2 hours, and cooled to 20°C to 30°C under reduced pressure.

[0013] Preferably, in step S1, the mass ratio of aminopolysilane to polyvinyl alcohol is (0.0625-0.75):1, the polyacid includes at least one of phytic acid, citric acid and tripolyphosphoric acid, and the ratio of polyvinyl alcohol, water and polyacid is (1 g):(5-7 mL):(3-5 mL).

[0014] Preferably, in step S1, the mixture is heated to 90° C. to 100° C. and reacted for 1 to 2 hours, and a polyacid is added and reacted for 1 to 2 hours.

[0015] Preferably, in step S2, the organic solvent includes at least one of ethanol, glycerol and dimethyl sulfoxide, and the volume concentration of the organic solvent in the aqueous solution of the organic solvent is 0% to 100% (excluding 0% and 100%); the solvent replacement time is 12 to 48 hours, and the number of solvent replacements is 1 to 3 times.

[0016] In a second aspect, the present invention provides an organic solvent-water dual solvent composite hydrogel obtained by the preparation method described in the first aspect.

[0017] In a third aspect, the present invention provides an application of the organic solvent-water dual solvent composite hydrogel as described in the second aspect in flexible sensing.

[0018] In a fourth aspect, the present invention provides a wearable strain sensor comprising the organic solvent-water dual solvent composite hydrogel as described in the second aspect.

[0019] The beneficial effects achieved by one or more technical solutions of the present invention are as follows:

[0020] Aminopolysilane was introduced into a polyvinyl alcohol (PVA) matrix and, through crosslinking with polyacids and freeze-thaw cycling, a silicone-reinforced PVA composite hydrogel was obtained. The PVA crosslinked through freeze-thaw cycling to form a primary network, while the polyacid-crosslinked aminopolysilane served as a secondary network. The two networks interpenetrated and connected by the polyacid. Furthermore, an organic solvent-water dual-solvent composite hydrogel was obtained through solvent replacement. By manipulating the type and concentration of the organic solvent, the mechanical, water-retention, and electrical properties of the composite hydrogel were improved.

[0021] The organic solvent-water dual-solvent composite hydrogel responds rapidly to different strains, has good cyclic stability, shows very high repeatability and extremely high sensitivity, can detect extremely small strain signals in real time, and the waveforms obtained are basically the same.

[0022] Organic solvent-water dual-solvent composite hydrogel can effectively monitor large-scale human body movements (large deformation) and facial micro-expression changes (small deformation). The signal detection is sensitive and stable, and it can be used as a wearable strain sensor material. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 (a) Photos of PVA / PA / APSi hydrogels immersed in different organic solvents, (b) Comparison of the morphology of the organic solvent-water dual solvent composite hydrogels of Examples 1 to 6 and the PVA / PA / APSi hydrogel of Comparative Example 1, (c) Comparison of the volume and mass of the PVA / PA / APSi hydrogels in Comparative Example 1, Example 1, Example 2, and Comparative Example 1 after water replacement, (d) Comparison of the volume and mass of the PVA / PA / APSi hydrogels in Comparative Example 1, Example 3, Example 4, and Comparative Example 1 after water replacement, (e) Comparison of the volume and mass of the PVA / PA / APSi hydrogels in Comparative Example 1, Example 5, Example 6, and Comparative Example 1 after water replacement;

[0025] Figure 2The stress-strain curves of the organic solvent-water dual solvent composite hydrogels of Examples 1 to 6 and the PVA / PA / APSi hydrogel of Comparative Example 1;

[0026] Figure 3 The loading-unloading cycle curves of the organic solvent-water dual solvent composite hydrogels of Examples 1 to 6 under different strains;

[0027] Figure 4 These are photos of the organic solvent-water dual-solvent composite hydrogels of Examples 1 to 6 and the PVA / PA / APSi hydrogel of Comparative Example 1 at different times at room temperature;

[0028] Figure 5 (a) The state of the Gly (50%) hydrogel of Example 3 at -50°C, (b) DCS curves of the hydrogels of Comparative Example 1, Example 3, and Example 4;

[0029] Figure 6 The linear relationship between (a) conductivity and (b) relative resistance change and strain of the organic solvent-water dual solvent composite hydrogels of Examples 1 to 6 and the PVA / PA / APSi hydrogel of Comparative Example 1;

[0030] Figure 7 The relative resistance change and stability of the Gly (50%) hydrogel in Example 7 under large strain (fingers, joints) and small strain (speaking, smiling). DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0032] Example 1

[0033] N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane (AEAPMDS, 105.3 g, 0.5 mol) and water (21.6 g, 1.2 mol) were mixed in a 500 mL three-necked flask and refluxed at 150°C for 1 hour under a N2 atmosphere. The mixture was then maintained at 150°C under vacuum for 1 hour to remove byproducts of methanol and water and further promote the condensation of siloxane molecules. The product was finally cooled to 25°C under reduced pressure to obtain a clear, viscous liquid aminopolysiloxane APSi (yield: 94%).

[0034] PVA (5.0 g) and APSi (1.875 g) were dissolved in deionized water (30 mL) in a 250 mL three-necked flask and stirred in an oil bath at 95°C for 1 h until the solution became clear. PA (20 mL) was continued to be added and stirred for 1 h until a clear mixture was obtained. The mixture was centrifuged at 4000 rpm for 10 minutes to remove bubbles and then poured into a mold. The mold was frozen at -20°C for 21 h and thawed at room temperature for 3 h. After repeating this process three times, a silicone-reinforced polyvinyl alcohol composite hydrogel (PVA / PA / APSi hydrogel) was obtained. Finally, the obtained PVA / PA / APSi hydrogel was soaked in distilled water for 24 hours and replaced three times to remove any residue.

[0035] like Figure 1 As shown in (a), the PVA / PA / APSi hydrogel was immersed in a 50% volume concentration ethanol (EtOH) aqueous solution for 12 hours to obtain an organic solvent-water dual solvent composite hydrogel, which was recorded as EtOH (50%) hydrogel.

[0036] Example 2

[0037] The preparation of aminopolysiloxane APSi is the same as in Example 1.

[0038] The preparation of PVA / PA / APSi hydrogel was the same as in Example 1.

[0039] like Figure 1 As shown in (a), the PVA / PA / APSi hydrogel was immersed in 100% ethanol for 12 hours to obtain an organic solvent-water dual solvent composite hydrogel, which was recorded as EtOH (100%) hydrogel.

[0040] Example 3

[0041] The preparation of aminopolysiloxane APSi is the same as in Example 1.

[0042] The preparation of PVA / PA / APSi hydrogel was the same as in Example 1.

[0043] like Figure 1 As shown in (a), the PVA / PA / APSi hydrogel was immersed in a 50% volume concentration of glycerol (Gly) aqueous solution for 12 hours to obtain an organic solvent-water dual solvent composite hydrogel, which was recorded as Gly (50%) hydrogel.

[0044] Example 4

[0045] The preparation of aminopolysiloxane APSi is the same as in Example 1.

[0046] The preparation of PVA / PA / APSi hydrogel was the same as in Example 1.

[0047] like Figure 1 As shown in (a), the PVA / PA / APSi hydrogel was immersed in 100% glycerol for 12 hours to obtain an organic solvent-water dual solvent composite hydrogel, which was recorded as Gly (100%) hydrogel.

[0048] Example 5

[0049] The preparation of aminopolysiloxane APSi is the same as in Example 1.

[0050] The preparation of PVA / PA / APSi hydrogel was the same as in Example 1.

[0051] like Figure 1 As shown in (a), the PVA / PA / APSi hydrogel was immersed in a 50% volume concentration dimethyl sulfoxide (DMSO) aqueous solution for 24 hours and replaced three times to obtain an organic solvent-water dual solvent composite hydrogel, which was recorded as DMSO (50%) hydrogel.

[0052] Example 6

[0053] The preparation of aminopolysiloxane APSi is the same as in Example 1.

[0054] The preparation of PVA / PA / APSi hydrogel was the same as in Example 1.

[0055] like Figure 1 As shown in (a), the PVA / PA / APSi hydrogel was immersed in 100% dimethyl sulfoxide for 12 hours to obtain an organic solvent-water dual solvent composite hydrogel, which was recorded as DMSO (100%) hydrogel.

[0056] Comparative Example 1

[0057] PVA / PA / APSi hydrogel was synthesized with reference to Example 1 for comparison.

[0058] like Figure 1 As shown, after the hydrogel was immersed in 50% EtOH solution and Gly solution for solvent replacement, its mass and volume were found to be significantly reduced. After being fully replaced in 100% EtOH and Gly, its mass and volume were reduced to about 40% of the original. This is because the molecular structure of the hydrogel is less compatible with EtOH and Gly than with water. When the hydrogel was immersed in 50% DMSO solution for full replacement, the mass and volume of the hydrogel were significantly reduced. When immersed in 100% DMSO, the mass and volume of the hydrogel increased to about 250% of the original, which may be because the molecular structure of the hydrogel is more compatible with DMSO than with water.

[0059] like Figure 2As shown in Table 1, the tensile strength of the hydrogels significantly increased after solvent exchange in EtOH and Gly. The tensile strength increased after solvent exchange in 50% DMSO, while it decreased after solvent exchange in 100% DMSO. The changes in the tensile strength of the hydrogels were consistent with the changes in mass and volume after solvent exchange, suggesting that the changes in the hydrogel mechanical properties are caused by changes in mass and volume.

[0060] Table 1 Tensile strength and elongation at break of hydrogels in Examples 1 to 6 and Comparative Example 1

[0061]

[0062] like Figure 3 As shown in the figure, the hysteresis loop of the hydrogel increases after solvent replacement, and the energy dissipation efficiency improves. This may be because the intermolecular interactions between these three organic solvents and water are stronger than between water and water, consuming more energy when force is applied. This also affects the mechanical properties of the hydrogel to some extent.

[0063] Hydrogels contain abundant free water and always suffer from severe dehydration, which greatly hinders their practical application scenarios and further commercialization. Figure 4 The dehydration photos of the hydrogels in Examples 1 to 6 and Comparative Example 1 at room temperature. It can be seen that the PVA / PA / APSi hydrogel in Comparative Example 1 completely lost water in 36 hours. The EtOH-replaced hydrogels in Examples 1 and 2 lost water faster due to the strong volatility of EtOH. The DMSO-replaced hydrogels in Examples 5 and 6 lost water more slowly. The Gly (50%) hydrogel in Example 5 showed good water retention due to the water-locking effect of Gly, and there was no obvious change in its morphology after being placed at room temperature for 168 hours. This is because Gly is relatively non-volatile and forms dense hydrogen bonds with water molecules to prevent the evaporation of water. In addition, the presence of hydrogen bonds also inhibits the formation of ice crystals, making the Gly (50%) hydrogel still soft at -50°C (such as Figure 5 From the DSC spectrum ( Figure 5 As can be seen in (b), as the Gly content increases, the freezing point of the Gly hydrogel gradually decreases from -12.3°C to below -120°C, which means that the Gly hydrogel can be used at low temperatures. Therefore, the introduction of Gly imparts both antifreeze and heat resistance to the hydrogel. The solvent substitution strategy is an effective means to improve the stability and applicability of hydrogels in various environments by replacing part of the water with organic molecules.

[0064] The electrical properties (conductivity, sensitivity coefficient, linear coefficient) of organic solvent-water dual solvent composite hydrogel also changed significantly. Figure 6As shown in (a), since the hydrogel is ion conductive, H + It mainly comes from the ionization of PA. In the mixed solvent, the ionization degree of PA is reduced, and the volume shrinkage of the hydrogel in the mixed solvent leads to a reduction in pore size, which is not conducive to the free shuttle of H+, so the conductivity of the hydrogel is reduced. Figure 6 As shown in (b), the hydrogel has a uniform network structure, so the resistance change of all organic solvent-water dual solvent composite hydrogels shows an obvious linear relationship with strain. As far as wearable strain sensors are concerned, the sensitivity coefficient (GF) is a relatively more important factor in electrical properties. As shown in Table 2, the GF of the Gly (50%) hydrogel of Example 3, the DMSO (50%) hydrogel of Example 5, and the DMSO (100%) hydrogel of Example 6 are much higher than that of the PVA / PA / APSi hydrogel, and the GF of the EtOH (50%) hydrogel of Example 2 is also higher than that of the PVA / PA / APSi hydrogel.

[0065] Table 2 Conductivity and GF of hydrogels in Examples 1 to 6 and Comparative Example 1, as well as linear fitting equations of relative resistance change and hydrogel strain

[0066]

[0067] Example 7

[0068] The Gly (50%) hydrogel of Example 3 was connected to a wire as a wearable strain sensor and attached to the fingers, wrists, knee joints, face and neck to test its cyclic stability under different strain conditions. Figure 7 As shown, Gly (50%) hydrogel responds rapidly to different strains, has good cyclic stability, and displays very high reproducibility and extremely high sensitivity. Furthermore, Gly (50%) hydrogel has a higher GF and can detect extremely small strain signals in real time, including smiling and talking, with the waveforms obtained being essentially the same. Gly (50%) hydrogel can be used as a wearable strain sensor to effectively monitor large human movements (large deformations) and micro-expression changes in the face (small deformations), with sensitive and stable signal detection.

[0069] Example 8

[0070] Different from Example 3, PVA (5.0 g) and APSi (0.3125 g) were dissolved in deionized water (30 mL) in a 250 mL three-necked flask.

[0071] Example 9

[0072] Different from Example 3, PVA (5.0 g) and APSi (0.625 g) were dissolved in deionized water (30 mL) in a 250 mL three-necked flask.

[0073] Example 10

[0074] Different from Example 3, PVA (5.0 g) and APSi (1.25 g) were dissolved in deionized water (30 mL) in a 250 mL three-necked flask.

[0075] Example 11

[0076] Different from Example 3, PVA (5.0 g) and APSi (1.875 g) were dissolved in deionized water (30 mL) in a 250 mL three-necked flask.

[0077] Example 12

[0078] Different from Example 3, PVA (5.0 g) and APSi (2.5 g) were dissolved in deionized water (30 mL) in a 250 mL three-necked flask.

[0079] Example 13

[0080] Different from Example 3, PVA (5.0 g) and APSi (3.75 g) were dissolved in deionized water (30 mL) in a 250 mL three-necked flask.

[0081] Example 14

[0082] 3-Aminopropyldimethylsilane (73.7 g, 0.5 mol) and water (21.6 g, 1.2 mol) were mixed in a 500 mL three-necked flask and refluxed at 150°C for 1 hour under a N2 atmosphere. The mixture was then maintained at 150°C under vacuum for 1 hour to remove byproducts of methanol and water and further promote the condensation of siloxane molecules. The product was finally cooled to 25°C under reduced pressure to obtain a clear, viscous liquid aminopolysilane.

[0083] PVA (5.0 g) and aminopolysilane (1.875 g) were dissolved in deionized water (30 mL) in a 250 mL three-necked flask and stirred in an oil bath at 95 ° C for 1 h until the solution became clear. Continue to add PA (20 mL) and stir for 1 h until a clear mixture is obtained. The mixture was centrifuged at 4000 rpm for 10 minutes to remove bubbles and then poured into a mold. The mold was frozen at -20 ° C for 21 h and thawed at room temperature for 3 h. After repeating this process three times, a silicone-enhanced polyvinyl alcohol composite hydrogel was obtained. Finally, the obtained silicone-enhanced polyvinyl alcohol composite hydrogel was soaked in distilled water for 24 hours and replaced three times to remove any residue.

[0084] The organosilicon reinforced polyvinyl alcohol composite hydrogel was immersed in a 50% volume concentration glycerol (Gly) aqueous solution for 12 hours to obtain an organic solvent-water dual solvent composite hydrogel.

[0085] Example 15

[0086] 3-Aminopropylmethyldimethoxysilane (81.6 g, 0.5 mol) and water (21.6 g, 1.2 mol) were mixed in a 500 mL three-necked flask and refluxed at 150°C for 1 hour under a N2 atmosphere. The mixture was then maintained at 150°C under vacuum for 1 hour to remove byproducts of methanol and water and further promote the condensation of siloxane molecules. The product was finally cooled to 25°C under reduced pressure to obtain a clear, viscous liquid aminopolysilane.

[0087] PVA (5.0 g) and aminopolysilane (1.875 g) were dissolved in deionized water (30 mL) in a 250 mL three-necked flask and stirred in an oil bath at 95 ° C for 1 h until the solution became clear. Continue to add PA (20 mL) and stir for 1 h until a clear mixture is obtained. The mixture was centrifuged at 4000 rpm for 10 minutes to remove bubbles and then poured into a mold. The mold was frozen at -20 ° C for 21 h and thawed at room temperature for 3 h. After repeating this process three times, a silicone-enhanced polyvinyl alcohol composite hydrogel was obtained. Finally, the obtained silicone-enhanced polyvinyl alcohol composite hydrogel was soaked in distilled water for 24 hours and replaced three times to remove any residue.

[0088] The organosilicon reinforced polyvinyl alcohol composite hydrogel was immersed in a 50% volume concentration glycerol (Gly) aqueous solution for 12 hours to obtain an organic solvent-water dual solvent composite hydrogel.

[0089] Example 16

[0090] N-(β-aminoethyl-γ-aminopropyl)methyldiethoxysilane (127.2 g, 0.5 mol) and water (21.6 g, 1.2 mol) were mixed in a 500 mL three-necked flask and refluxed at 150° C. for 1 hour under a N2 atmosphere. The mixture was then maintained at 150° C. under vacuum for 1 hour to remove byproducts of methanol and water and further promote the condensation of siloxane molecules. The product was finally cooled to 25° C. under reduced pressure to obtain a clear, viscous liquid aminopolysilane.

[0091] PVA (5.0 g) and aminopolysilane (1.875 g) were dissolved in deionized water (30 mL) in a 250 mL three-necked flask and stirred in an oil bath at 95 ° C for 1 h until the solution became clear. Continue to add PA (20 mL) and stir for 1 h until a clear mixture is obtained. The mixture was centrifuged at 4000 rpm for 10 minutes to remove bubbles and then poured into a mold. The mold was frozen at -20 ° C for 21 h and thawed at room temperature for 3 h. After repeating this process three times, a silicone-enhanced polyvinyl alcohol composite hydrogel was obtained. Finally, the obtained silicone-enhanced polyvinyl alcohol composite hydrogel was soaked in distilled water for 24 hours and replaced three times to remove any residue.

[0092] The organosilicon reinforced polyvinyl alcohol composite hydrogel was immersed in a 50% volume concentration glycerol (Gly) aqueous solution for 12 hours to obtain an organic solvent-water dual solvent composite hydrogel.

[0093] Example 17

[0094] Trimethoxy[3-(methylamino)propyl]silane (96.7 g, 0.5 mol) and water (21.6 g, 1.2 mol) were mixed in a 500 mL three-necked flask and refluxed at 150°C for 1 hour under a N2 atmosphere. The mixture was then maintained at 150°C under vacuum for 1 hour to remove byproducts of methanol and water and further promote the condensation of siloxane molecules. The product was finally cooled to 25°C under reduced pressure to obtain a clear, viscous liquid aminopolysilane.

[0095] PVA (5.0 g) and aminopolysilane (1.875 g) were dissolved in deionized water (30 mL) in a 250 mL three-necked flask and stirred in an oil bath at 95 ° C for 1 h until the solution became clear. Continue to add PA (20 mL) and stir for 1 h until a clear mixture is obtained. The mixture was centrifuged at 4000 rpm for 10 minutes to remove bubbles and then poured into a mold. The mold was frozen at -20 ° C for 21 h and thawed at room temperature for 3 h. After repeating this process three times, a silicone-enhanced polyvinyl alcohol composite hydrogel was obtained. Finally, the obtained silicone-enhanced polyvinyl alcohol composite hydrogel was soaked in distilled water for 24 hours and replaced three times to remove any residue.

[0096] The organosilicon reinforced polyvinyl alcohol composite hydrogel was immersed in a 50% volume concentration glycerol (Gly) aqueous solution for 12 hours to obtain an organic solvent-water dual solvent composite hydrogel.

[0097] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing an organic solvent-water dual solvent composite hydrogel, characterized in that: The following steps are involved: S1. Dissolving aminopolysilane and polyvinyl alcohol in water and heating for reaction, adding a polyacid to react to obtain a mixture, and subjecting the mixture to centrifugation and cyclic freeze-thaw to obtain an organosilicon-reinforced polyvinyl alcohol composite hydrogel, wherein the mass ratio of aminopolysilane to polyvinyl alcohol is (0.0625-0.75):1, the polyacid comprises at least one of phytic acid, citric acid, and tripolyphosphoric acid, and the ratio of polyvinyl alcohol, water, and polyacid is (1 g):(5-7 mL):(3-5 mL); S2, the silicone reinforced polyvinyl alcohol composite hydrogel is placed in an aqueous solution of an organic solvent for solvent replacement to obtain an organic solvent - water dual solvent composite hydrogel, the volume concentration of the organic solvent in the aqueous solution of the organic solvent is 50%; In step S2, the organic solvent is dimethyl sulfoxide.

2. The preparation method according to claim 1, wherein In step S1, the aminopolysilane is prepared by mixing aminosilane and water, heating and refluxing, removing water in a vacuum, and cooling under reduced pressure.

3. The preparation method according to claim 2, wherein The aminosilane includes at least one of 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)methyldimethoxysilane, N-(β-aminoethyl-γ-aminopropyl)methyldiethoxysilane and trimethoxy[3-(methylamino)propyl]silane, and the molar ratio of the aminosilane to water is 1:(2~5).

4. The preparation method according to claim 2, wherein Heat to 140℃~160℃ in N2 atmosphere and reflux for 1~2h, remove water in vacuum at 140℃~160℃ for 1~2h, and cool to 20℃~30℃ under reduced pressure.

5. The preparation method according to claim 1, wherein In step S1, the mixture is heated to 90°C to 100°C and reacted for 1 to 2 hours, and a polyacid is added and reacted for 1 to 2 hours.

6. An organic solvent-water dual solvent composite hydrogel, characterized in that: The method is obtained by the preparation method according to any one of claims 1 to 5.

7. Use of the organic solvent-water dual solvent composite hydrogel as claimed in claim 6 in flexible sensing.

8. A wearable strain sensor, characterized in that It comprises the organic solvent-water dual solvent composite hydrogel as described in claim 6.

Images