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CN-122011298-A - Mechanically-interlocked polyrotaxane conductive hydrogel and preparation method and application thereof

CN122011298ACN 122011298 ACN122011298 ACN 122011298ACN-122011298-A

Abstract

The invention discloses a mechanically interlocked polyrotaxane conductive hydrogel and a preparation method and application thereof, the hydrogel is prepared by taking quasi-rotaxane formed by self-assembly of a water-soluble allyl functionalized naphthalene tube and polyethylene glycol diacrylate as a dynamic crosslinking unit and performing one-step photopolymerization on the quasi-rotaxane and an ethylene monomer. The hydrogel has ultrahigh stretchability (fracture strain > 2450%), skin-like low modulus (about 8.5 kPa), excellent fatigue resistance, high ionic conductivity (7.46 mS/cm) and strong interfacial adhesion. Also discloses the application of the hydrogel in preparing high-performance flexible strain sensors and bioelectrodes. In the bioelectrode, stable conformal contact can be formed with skin, high-fidelity and motion artifact-resistant electrocardio and electromyographic signal acquisition is realized, and the signal to noise ratio is still kept above 34 dB under dynamic motion. The invention has simple preparation process and good biocompatibility, and has wide application prospect in the fields of wearable medical monitoring and man-machine interaction.

Inventors

  • HUANG LIPING
  • HUANG HAOZHENG

Assignees

  • 广西师范大学

Dates

Publication Date
20260512
Application Date
20260206

Claims (10)

  1. 1. The mechanically interlocked polyrotaxane conductive hydrogel is characterized by being prepared from a reaction system comprising the following components by one-step photopolymerization: (a) A dynamic crosslinking unit, which is a quasimethide structure formed by self-assembling a water-soluble allyl functionalized naphthalene tube (ANT) and polyethylene glycol diacrylate (PEG-DA) through interaction of a host and a guest, wherein the ANT structure comprises a naphthalene tube framework, carboxylate or carboxylate groups modified on the outer side of the framework to provide water solubility, and polymerizable allyl modified on the tail end of the framework; (b) Ethylene functional monomers including neutral ethylene monomers and ionizable ethylene monomers; (c) A photoinitiator; the photopolymerization reaction enables the acrylate double bond at the tail end of PEG-DA and the allyl double bond at the tail end of ANT to participate in covalent crosslinking, so that a mechanical interlocking topological structure with a static covalent crosslinking network and a dynamic slip ring crosslinking point based on quasimethide is formed.
  2. 2. The mechanically interlocking polyrotaxane electrically conductive hydrogel as recited in claim 1 wherein the water-soluble allylic functionalized naphthalene tube (ANT) has a general structure represented by the following formula (1): ; Formula (1).
  3. 3. The mechanically interlocking polyrotaxane electrically conductive hydrogel of claim 1 wherein the PEG-DA has a molecular weight of from 10 kDa to 35 kDa.
  4. 4. The mechanically interlocking polyrotaxane electrically conductive hydrogel of claim 1 wherein the molar ratio of ANT to PEG-DA is from 1:1 to 5:1.
  5. 5. The mechanically interlocking polyrotaxane electrically conductive hydrogel of claim 1 wherein the neutral vinyl monomer comprises at least one of acrylamide, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, hydroxypropyl methacrylate, N-trimethylol methacrylamide, N- (2-hydroxypropyl) methacrylamide, methyl methacrylate, glycidyl methacrylate; The ionizable ethylene monomer comprises at least one of acrylic acid, methacrylic acid, sodium acrylate, lithium acrylate, potassium acrylate, itaconic acid, 3- [ N, N-dimethyl- [2- (2-methylprop-2-enoyloxy) ethyl ] ammonium ] propane-1-sulfonic acid inner salt, [3- (methacrylamido) propyl ] dimethyl (3-thiopropyl) ammonium hydroxide, acryloyloxyethyl trimethyl ammonium chloride and methacryloyloxyethyl trimethyl ammonium chloride.
  6. 6. The mechanically interlocking polyrotaxane electrically conductive hydrogel of claim 5 wherein the mass ratio of neutral vinylic monomer to ionizable vinylic monomer is from 1:10 to 10:1.
  7. 7. A method of preparing a mechanically interlocking polyrotaxane electrically conductive hydrogel as defined in any of claims 1 to 6, comprising the steps of: S1, mixing a water-soluble allyl functionalized naphthalene pipe (ANT) and polyethylene glycol diacrylate (PEG-DA) in water to enable the ANT to penetrate into a PEG-DA chain, and self-assembling to form a quasimethide cross-linking agent solution; S2, uniformly mixing the quasimethine cross-linking agent solution obtained in the step S1, the ethylene functional monomer and the photoinitiator in water to obtain a precursor solution; and S3, placing the precursor solution in a mould, and carrying out polymerization reaction under ultraviolet irradiation to obtain the mechanically interlocked polyrotaxane conductive hydrogel.
  8. 8. A flexible strain sensor, characterized in that its sensing unit is constituted by a mechanically interlocking polyrotaxane conductive hydrogel according to any of claims 1 to 6.
  9. 9. A bioelectrode comprising an electrode substrate and a conductive gel layer disposed on said electrode substrate, said conductive gel layer being comprised of the mechanically interlocking polyrotaxane conductive hydrogel of any of claims 1-6.
  10. 10. Use of the bioelectrode according to claim 9 for acquiring human electrocardiosignals or myoelectric signals.

Description

Mechanically-interlocked polyrotaxane conductive hydrogel and preparation method and application thereof Technical Field The invention relates to the technical field of functional polymer materials and flexible electronics, in particular to a conductive hydrogel with a mechanical interlocking topological structure, a preparation method thereof and application of the hydrogel in a flexible strain sensor and a bioelectrode. Background Because of its flexibility, hydrophilicity and ionic/electronic conductivity, conductive hydrogels have become ideal candidates in flexible electronics, biosensors and wearable health monitoring systems. The material can form good conformal contact with human skin, so that comfortable, long-term and high-fidelity physiological signal acquisition is expected to be realized. However, conventional conductive hydrogels rely primarily on static covalent cross-linked networks or weak physical interactions, resulting in materials with ubiquitous problems of insufficient mechanical properties (e.g., toughness, elongation at break, fatigue resistance). Under the repeated action of dynamic deformation (such as joint bending and skin stretching), the network structure is easy to be irreversibly damaged or broken, and meanwhile, the internal conductive paths (whether ion migration paths or filler conductive networks) are also easy to be damaged. This is directly manifested by drift of the sensing signal, reduced signal-to-noise ratio and poor long-term stability, and is difficult to meet the urgent demands for high reliability and high fidelity signal acquisition in a motion state or long-term continuous monitoring scene. The polyrotaxane is used as a typical mechanical interlocking molecular structure, and can effectively dissipate energy and improve mechanical properties through a molecular pulley effect. In this structure, macrocyclic molecules are threaded onto linear polymer chains and can slide along the chains. Integration of such topologies into hydrogel networks can effectively dissipate external force energy through reversible sliding of the macrocycles, thereby imparting excellent toughness, stretchability, and fatigue resistance to the material. However, the application of polyrotaxane structures in conductive hydrogels is limited by suitable macrocyclic molecules (which require both water solubility, strong host-guest recognition and polymerizability) and cumbersome multi-step preparation processes. Most of the currently reported polyrotaxane hydrogels are based on cyclodextrin systems, the material types and performance regulation means are relatively single, and the diversified application requirements are difficult to meet. More importantly, the construction of the traditional polyrotaxane generally requires a complex end-capping step to prevent the macrocyclic ring from falling out, has complicated synthesis process, and is difficult to be compatible with a simple one-step molding process of hydrogel, which severely restricts the large-scale preparation and application of the polyrotaxane structure in flexible electronic devices. In the prior art, for example, a polyrotaxane quasi-slip ring hydrogel of a comparison document CN115124662B, a preparation method and application thereof, a naphthalene tube NT containing carboxyl and PEG-DA are used for forming dynamic cross-linking through hydrogen bonds, and the emphasis is placed on realizing mechanical enhancement through mechanical training. However, in the method, the macrocyclic molecules are not covalently connected with the polymer network, so that a mechanical interlocking structure cannot be formed, the mechanical properties of the macrocyclic molecules are not different from those of common covalent crosslinking hydrogel materials, and external stress cannot be dissipated through a slip ring effect. The dynamic cross-linking depends on hydrogen bonds, and under long-term or severe dynamic use, stress concentration easily occurs, and the long-term stability of the structure and the reliability of signal acquisition are affected. Therefore, developing a novel macrocyclic molecule and a construction strategy for synchronously realizing quasi-rotaxane end capping and network crosslinking by a high-efficiency one-pot method matched with the novel macrocyclic molecule to construct the mechanically interlocked polyrotaxane conductive hydrogel with excellent comprehensive performance becomes a key for solving the problems and promoting the development of high-performance flexible bioelectrodes. Disclosure of Invention The invention aims to overcome the defects of the prior art, and the primary aim is to provide a novel water-soluble and polymerizable allyl functionalized naphthalene (ANT) macrocyclic molecule. The second aim is to provide a pseudo rotaxane dynamic crosslinking unit based on the ANT and the PEG-DA and a preparation method thereof. A third object is to provide a method for preparing a mechanically interlocking