Preparation Of P(AM-co-AA)-based Functional Hydrogel And Performance Study

As a soft and wet material with high moisture content,hydrogel has attracted wide attention in many fields such as bionic skin,cartilage scaffold,rehabilitation monitoring and soft robot.Traditional hydrogel sensors have poor mechanical properties,easy to breed bacteria and other defects,it is difficult to apply to outdoor camping,wilderness exploration and other harsh environment.Therefore,there is an urgent need for a tough,antibacterial,conductive hydrogel material to meet the complex human motion monitoring and the growing demand for wearable devices.In this study,a novel method was used to prepare a wearable hydrogel sensor with antibacterial,electrical conductivity,antioxidant,adhesion and high sensitivity.Specific research contents are as follows:Part I:Traditional single crosslinked hydrogels have poor mechanical properties,general sensitivity and easy to breed bacteria,so they are not suitable for application in the field of flexible wearable devices.In this system,P（AM-Co-AA）/HACC hydrogels were prepared by double physical crosslinking method with acrylamide（AM）and acrylic acid（AA）as the main body,and quaternary ammonium chitosan（HACC）was introduced.Then soaked in Fe³⁺solution,HACC/P（AM-co-AA）-Fe³⁺ion crosslinked hydrogels with high strength and toughness were prepared.During the immersion process,the amino（-NH₂）of HACC and the rich carboxyl（-COOH）on the copolymer chain are highly coordinated with the high price metal Fe³⁺to form a cross-linked network of multiple heavy ions,which greatly improves the mechanical properties of hydrogels（tensile stress is 3 MPa,fracture strain is 1390%,toughness is 24 MJ/m³）.Free ammonium ions(-Nr³⁺),Fe³⁺and Cl^-give the hydrogel good conductivity and sensitivity（conductivity of 21.6 m S/cm,GF=10.27）.The introduction of quaternary ammonium chitosan brings strong bacteriostasis for hydrogels（the highest bacteriostasis efficiency is 99.5%）.This work provides an effective strategy for the preparation of a new type of strong antibacterial conductive hydrogel with multiple cross-linked networks.PartⅡ:In this study,acrylamide（AM）and acrylic acid（AA）were also used as the main body,and transition metal carbide（MXene）,quaternary ammonium chitosan（HACC）and phytic acid（PA）were introduced into P（AM-Co-AA）hydrogel system.P（AM-co-AA）/HACC/MXene/PA composite hydrogels with excellent mechanical properties,adhesion,oxidation resistance and electrical conductivity were prepared.The introduced MXene and HACC can form a large number of hydrogen bonds with polymer molecular chains,thus effectively improving the mechanical properties of hydrogels（tensile strength,elongation at break,elastic modulus and fracture toughness of 1900 KPa,3500%,32 KPa and 32 MJ/m³,respectively）.At the same time,the introduction of HACC can also improve the adhesion of hydrogel（the strongest peeling strength is 127.51 N/m）.In addition,PA and MXene in the composite hydrogels can not only effectively improve the conductivity and sensitivity of the composite hydrogels through synergistic conduction（the maximum conductivity is 25.1m S/cm,GF=13.41）,but also provide excellent oxidation resistance for the hydrogels.This research provides a new design idea and theoretical basis for the application of hydrogels in the field of conductivity and oxidation resistance of sensors.