Preparation method and application of NaSCN-mediated adhesive polyvinyl alcohol hydrogel
Through the NaSCN-mediated polyvinyl alcohol hydrogel preparation method, a ternary composite hydrogel system was constructed, which solved the problem of insufficient adhesion of polyvinyl alcohol hydrogel and achieved a hydrogel with high adhesion and mechanical flexibility, which is suitable for wearable electronic devices and biological interfaces.
Patent Information
- Application Number
- CN202510932547.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-07
- Publication Date
- 2025-10-10
AI Technical Summary
Existing polyvinyl alcohol hydrogels have insufficient adhesion in three-dimensional polymer networks, especially exhibiting poor adhesion at wet or soft tissue interfaces, limiting their application potential in wearable electronic devices, biointerfaces, and medical dressings.
By introducing NaSCN and mixing it with PVA and polymer monomers such as PAM, DMA, HEMA, a ternary composite hydrogel system is constructed to regulate the water molecular structure and the interaction between polymer chain segments and enhance adhesion.
The prepared PAM-PVA-NaSCN hydrogel exhibits excellent adhesion strength and stability on a variety of substrates, low Young's modulus and high ionic conductivity, making it suitable for flexible sensors and reliable monitoring of biological signals.
Smart Images
Figure CN120757808A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of functional polymer materials, and particularly relates to a preparation method and application of a NaSCN-mediated adhesive polyvinyl alcohol hydrogel. Background Art
[0002] Polyvinyl alcohol (PVA) is a water-soluble polymer rich in hydroxyl groups. It has excellent biocompatibility, low toxicity, processability, and film-forming properties, and is widely used in food, medicine, biomaterials, and functional polymer materials. Thanks to its strong hydrophilicity and the large number of hydroxyl groups on its molecular chain, aqueous PVA solutions can form hydrogen bond networks and physical penetration bonds with the surfaces of various substrates (such as glass, metal, plastic, and skin) at room temperature, exhibiting good adhesion and often used as a cost-effective liquid adhesive. However, when PVA is embedded in a three-dimensional polymer network to form a hydrogel, its intrinsic adhesion ability is often significantly weakened, especially at interfaces such as wet or soft tissues, where it exhibits poor adhesion, severely restricting its potential for application in wearable electronics, biointerfaces, and medical dressings. Summary of the Invention
[0003] The present invention aims to provide a method for preparing NaSCN-mediated adhesive polyvinyl alcohol hydrogels to address the insufficient adhesiveness of existing polyvinyl alcohol hydrogels. The hydrogels prepared by this method exhibit good electrical conductivity, low Young's modulus, and excellent interfacial adhesion, demonstrating their potential for applications in wearable electronics, biointerfaces, and medical dressings.
[0004] The preparation method of the NaSCN-mediated adhesive polyvinyl alcohol hydrogel of the present invention comprises the following steps: Step 1: PVA solution and NaSCN were mixed to prepare PVA-NaSCN composite solution A.
[0005] Step 2: Adding a high molecular weight monomer, a photoinitiator, and a cross-linking agent to the composite solution A, polymerizing under ultraviolet light initiation to obtain a target product.
[0006] In step 1, the concentration of the PVA solution is 12-18 wt %, and the solid content ratio of NaSCN to PVA is 1.5-7 g / g.
[0007] In step 2, the high molecular weight monomer is selected from one or a combination of two or more of acrylamide, acrylic acid, N,N-dimethylacrylamide (DMA), and 2-hydroxyethyl methacrylate (HEMA) in any ratio.
[0008] Furthermore, the mass ratio of the high molecular weight monomer to PVA is 1.5-3 g / g.
[0009] In step 2, the cross-linking agent is N,N-methylenebisacrylamide, and the added mass is 1-3‰ of the mass of the high molecular weight monomer.
[0010] In step 2, the photoinitiator is methyl propiophenone (I1173), and the added mass is 1-5‰ of the mass of the polymer monomer.
[0011] In step 2, the UV-light initiation time is 300-800 s.
[0012] Application of the NaSCN-mediated adhesive polyvinyl alcohol hydrogel in the preparation of flexible sensors.
[0013] This invention utilizes NaSCN's destructive manipulation of water molecular structure and interactions between polymer segments to construct a novel self-adhesive hydrogel system. This invention uses highly hydrophilic polymers with excellent mechanical properties and good network compatibility with PVA, such as polyacrylamide (PAM), N,N-dimethylacrylamide (DMA), and 2-hydroxyethyl methacrylate (HEMA), as the main matrix. By introducing PVA and NaSCN, a ternary composite hydrogel system is constructed. In a 90° peel test, the PAM-PVA-NaSCN exhibited an adhesion strength of approximately 75 N / m on a wood surface. Furthermore, the PAM-PVA-NaSCN maintained good adhesion after 15 cycles of application to the same substrate, demonstrating excellent stability and repeatability. Furthermore, the hydrogel exhibits good adhesion to a variety of substrates, including iron, glass, plastic, pigskin, rubber, PP, pig liver, and pig kidney, demonstrating broad adaptability and potential for application.
[0014] Compared with the prior art, the present invention has the following advantages: 1. In the present invention, by regulating the segmentation effect induced by NaSCN salt, the physical aggregation morphology of PVA in the PAM and other hydrogel networks is adjusted, thereby achieving an effective transformation from non-adhesive PAM-PVA hydrogel to adhesive PAM-PVA-NaSCN hydrogel.
[0015] 2. In the present invention, due to the mediation of NaSCN, the hydrogel has excellent mechanical flexibility (Young's modulus ~0.046MPa), high ionic conductivity (~1.48 RS / m) and good dehydration resistance.
[0016] 3. The PAM-PVA-NaSCN hydrogel prepared in this invention exhibits exceptionally strong adhesion, forming a close, conformable contact with human skin, enabling reliable monitoring of motion and biosignals. This invention plays a significant role in advancing strategies based on the Hofmeister effect and the development of self-adhesive hydrogels. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 Comparison of digital photos of the adhesion properties of different PAM hydrogels prepared using untreated and NaSCN-treated PVA. Figure 1 It can be seen that the PVA-PAM hydrogel treated with NaSCN has good adhesion, and when the finger is placed on the surface of the gel, obvious stringing behavior occurs.
[0018] Figure 2 Figure 2 shows the force-displacement curves and corresponding peel strength values obtained from the 90° peel test of PAM-PVA and PAM-PVA-NaSCN hydrogels (test substrate: wood). Figure 2 It can be seen that PVA-PAM hydrogel has almost no adhesion, while the adhesion strength of PAM-PVA-NaSCN hydrogel is as high as 75 N / m.
[0019] Figure 3 (a) Repeated adhesion performance of PAM-PVA-NaSCN hydrogel to wood substrate after 15 adhesion-peeling cycles; (b) Adhesion strength of PAM-PVA-NaSCN hydrogel to different substrates; (c) Photographs showing the excellent adhesion performance of PAM-PVA-NaSCN hydrogel to various substrates. Figure 3 As can be seen in the figure, the PAM-PVA-NaSCN hydrogel maintains good adhesion to wood after 15 cycles of adhesion and peeling, with little change in adhesion strength. The gel also exhibits good adhesion to iron sheets, pigskin, glass, and plastic. It also exhibits good adhesion to common materials such as rubber, PP, pig liver, and pig kidney.
[0020] Figure 4 Force-displacement curves of (a) P(AA-co-AM)-PVA and P(AA-co-AM)-PVA-NaSCN; (b) PDMA-PVA and PDMA-PVA-NaSCN; (c) PHEMA-PVA and PHEMA-PVA-NaSCN hydrogels obtained in 90° peel test. Figure 4 It can be seen that NaSCN is not only suitable for regulating the adhesion of PVA-PAM hydrogels, but can also be further promoted and expanded, and is still applicable to P(AA-co-AM)-PVA-NaSCN, PDMA-PVA-NaSCN and PHEMA-PVA-NaSCN hydrogels.
[0021] Figure 5 Comparison of (a) ECG and (b) EMG testing between PAM-PVA-NaSCN hydrogel and commercial electrodes. Figure 5It can be seen that PAM-PVA-NaSCN hydrogel is comparable to commercial electrodes for testing ECG signals and EMG signals, and its signal-to-noise ratio is even lower than that of commercial electrodes, making it a good candidate material for commercial electrodes in the future. DETAILED DESCRIPTION
[0022] The method of the present invention is further described in detail below with reference to the examples. It should be noted that the scope of protection of the present invention should include but not be limited to the technical content disclosed in the examples.
[0023] Example 1: 1. Dissolve PVA in deionized water and heat to prepare a 15% PVA solution. Mix 20 g of the PVA solution with 20 g of NaSCN to prepare a PVA-NaSCN composite solution.
[0024] 2. Add 6 g AM, 6 mg MBA, and 9 mg photoinitiator 1173 to the PVA-NaSCN composite solution. After thorough mixing, cure under UV light to obtain PAM-PVA-NaSCN hydrogel.
[0025] The same method was used, except that NaSCN was not added, to prepare PAM-PVA hydrogel for comparison.
[0026] Example 2: 1. Dissolve PVA in deionized water and heat to prepare a 15% PVA solution. Mix 20 g of the PVA solution with 18 g of NaSCN to prepare a PVA-NaSCN composite solution.
[0027] 2. Add 3 g AM, 3 g AA, 6 mg MBA, and 9 mg photoinitiator 1173 to the PVA-NaSCN composite solution. After thorough mixing, cure under UV light to obtain P(AA-co-AM)-PVA-NaSCN hydrogel.
[0028] The same method was used, except that NaSCN was not added, to prepare P(AA-co-AM)-PVA hydrogel for comparison.
[0029] Example 3: 1. Dissolve PVA in deionized water and heat to prepare a 15% PVA solution. Mix 20 g of the PVA solution with 17 g of NaSCN to prepare a PVA-NaSCN composite solution.
[0030] 2. Add 5 g DMA, 1 g AM, 6 mg MBA, and 9 mg photoinitiator 1173 to the PVA-NaSCN composite solution. After thorough mixing, cure under UV light to obtain PDMA-PVA-NaSCN hydrogel.
[0031] The same method was used, except that NaSCN was not added, to prepare PDMA-PVA hydrogel for comparison.
[0032] Example 4: 1. Dissolve PVA in deionized water and heat to prepare a 15% PVA solution. Mix 20 g of the PVA solution with 18 g of NaSCN to prepare a PVA-NaSCN composite solution.
[0033] 2. Add 6 g HEMA, 6 mg MBA, and 9 mg photoinitiator 1173 to the PVA-NaSCN composite solution. After thorough mixing, cure under UV light to obtain PHEMA-PVA-NaSCN hydrogel.
[0034] The same method was used, except that NaSCN was not added, to prepare PHEMA-PVA hydrogel for comparison.
[0035] Example 5: 1. Dissolve PVA in deionized water and heat to prepare a 16% PVA solution. Mix 20 g of the PVA solution with 18 g of NaSCN to prepare a PVA-NaSCN composite solution.
[0036] 2. Add 6 g AM, 6 mg MBA, and 9 mg photoinitiator 1173 to the PVA-NaSCN composite solution. After thorough mixing, cure under UV light to obtain PAM-PVA-NaSCN hydrogel.
[0037] The same method was used, except that NaSCN was not added, to prepare PAM-PVA hydrogel for comparison.
Claims
1. A method for preparing a NaSCN-mediated adhesive polyvinyl alcohol hydrogel, characterized in that: Sodium thiocyanate was introduced into the PVA solution to form a dissociated PVA composite system, which was further introduced into a hydrophilic polymer network to construct a polymer-PVA-NaSCN composite hydrogel.
2. The preparation method according to claim 1, wherein The steps include: Step 1: PVA solution and NaSCN were mixed to prepare PVA-NaSCN composite solution A; Step 2: adding a polymer monomer, a photoinitiator, and a crosslinking agent to the composite solution A, and polymerizing under ultraviolet light to obtain a target product; The high molecular weight monomer is selected from one or a combination of two or more of acrylamide, acrylic acid, N,N-dimethylacrylamide, and 2-hydroxyethyl methacrylate in any ratio.
3. The preparation method according to claim 2, wherein: In step 1, the concentration of the PVA solution is 12-18 wt %, and the solid content ratio of NaSCN to PVA is 1.5-7 g / g.
4. The preparation method according to claim 2, wherein: The mass ratio of the high molecular weight monomer to PVA is 1.5-3 g / g.
5. The preparation method according to claim 2, wherein: In step 2, the cross-linking agent is N,N-methylenebisacrylamide.
6. The preparation method according to claim 5, characterized in that: The added mass of the cross-linking agent is 1-3‰ of the mass of the high molecular monomer.
7. The preparation method according to claim 2, characterized in that: In step 2, the photoinitiator is methyl propiophenone.
8. The preparation method according to claim 7, characterized in that: The added mass of the photoinitiator is 1-5‰ of the mass of the high molecular monomer.
9. The preparation method according to claim 2, wherein: In step 2, the UV-light initiation time is 300-800 s.
10. Use of the NaSCN-mediated adhesive polyvinyl alcohol hydrogel prepared by the preparation method according to any one of claims 1 to 9 in the preparation of flexible sensors.