Construction And Application Of Functional Self-healing Hydrogel System

Hydrogel is a cross-linked three-dimensional network polymer material with excellent hydrophilicity,flexibility,and biocompatibility.Hydrogel materials with various excellent properties can be constructed through structural design,such as self-healing,electrical conductivity,and stimulus response.In recent years,hydrogels have been widely researched and have a wide range of applications in flexible sensing,wearable devices,tissue engineering,and,biomedicine.Hydrogels with self-healing performance could achieve self-healing after material damage and improve the service life of materials,which is urgently needed in many application fields.In this paper,starting from the structural design,multifunctional self-healing hydrogels were constructed and their applications in flexible sensors and information encoding were studied.The main contents include:1.A self-healing conductive hydrogel based on polysaccharide biomacromolecules oxidized sodium alginate（OSA）,carboxymethyl chitosan（CMC）,agarose（AGO）,and Li Cl was constructed.Among them,the hydroxyl group of OSA and the amino group of CMC form an imine bond（Schiff base）dynamic structure,which endows the hydrogel self-healing property;the double-helix struc2ture after cooling of AGO improves the mechanical property of the hydrogel;The presence of Li⁺and Cl^-ions in water improves the electrical conductivity of the hydrogel.More importantly,the resistance of the hydrogel changes with the shape of the hydrogel.Therefore,the application of the hydrogel in the field of flexible sensors is further studied,which can be used in finger flexible sensors to transmit the compressed information and monitor the process of finger sliding on mobile phones to browse web pages.2.Electrostatic self-healing hydrogels based on acrylamide（AM）,acrylic acid（AA）,and 2-（dimethylamino）ethyl methacrylate（DMAEMA）were constructed.Polyoxometalate ammonium heptamolybdate（Mo₇）and polymerizable coumarin-based derivative（AHPMC）were introduced,respectively,which endow the hydrogels with excellent photochromic and photoluminescent photoresponsive properties.According to the reversibility of electrostatic bonding between the carboxyl group of AA and the tertiary amino group of DMAEMA,the hydrogel possesses good self-healing property.The valence state of Mo₇gradually decreases under UV light irradiation and thus the color changes.The AHPMC emits blue fluorescence under UV light irradiation.More importantly,by programming and combining the above three hydrogels and self-healing,different parts of the hydrogel combination will have different responses under UV light irradiation.Therefore,the application of hydrogels in information coding display and encryption was further studied.