Preparation And Study Of High Performance Polyacrylic Hydrogel And Polymer Supercapacitors

Hydrogel materials have great application prospects in biomedicine,sensors,energy storage devices,environmental engineering,etc.due to their unique physical and chemical properties such as water absorption,remodeling,and sensitivity.The degree of concern also puts forward higher requirements on the mechanical properties of hydrogels.By optimizing the composition and structural design of the hydrogel,the mechanical properties of the hydrogel can be improved.Physically cross-linked hydrogels and composite cross-linked hydrogels have been extensively studied for their excellent tensile ability,strength,and self-healing ability.In this paper,the polythiourea structure is introduced into the polyacrylic acid(PAA)hydrogel system to increase the density of hydrogen bonding within the hydrogel,and then through chemical cross-linking,hydrophobic interaction and electrostatic interaction to improve the mechanical properties of hydrogels.Finally,we conducted a preliminary exploration of the application of hydrogels in solid supercapacitors.The main work and results are as follows:1.Prepared amphiphilic triblock polymer LTL with polythiourea as the middle block,polylysine as the end block and vinylated polythiourea MT.The triblock polymer LTL and MT self-assemble through hydrogen bonding in aqueous solution to form LTL/MT micelles.Using LTL/MT micelles as macromolecular cross-linking agents,a high-performance PAA/LTL/MT hydrogel has been developed.Due to hydrogen bonding,electrostatic interaction,and chemical crosslinking,PAA/LTL/MT hydrogels exhibit elongation of up to 78 times,fracture energy of 1.75 MJ/m3,and maximum true stress of 4.8 MPa.At the same time,the energy dissipation of the hydrogel reached 40%of the total tensile work,and the self-healing rate reached more than 80%in 24 hours.Due to the porous structure of the PAA/LTL/MT hydrogel,after the introduction of potassium chloride ions,the hydrogel shows good ion conductivity and has potential electronic application value.2.In order to further improve the recovery ability,self-healing ability and remodeling ability of PAA hydrogel,we designed and successfully synthesized the triblock polymer MNTNM through RAFT.The middle block is still polythiourea with high-density hydrogen bonds,both ends of the block have a hydrophobic group and a hydrogen bond structure.Hydrogen-bonded MNTNM micelles was used as a physical crosslinking agent,to develop high-performance pure physical PAA/MNTNM hydrogels.Thanks to hydrogen bonding and hydrophobic protection,as well as electrostatic interaction,the hydrogel exhibits excellent elongation of up to 75 times and a fracture energy of 1.8 MJ/m3,and its maximum true stress can reach 3.5 MPa.The hydrogel also has excellent resilience performance,and the self-healing efficiency is more than 80%in 24 hours.At the same time,the hydrogel also has the ability to remodel.PAA/MNTNM hydrogels have excellent electrical properties and a sensitivity of 2.53 during stretching,which has potential application value in strain sensors.3.The application prospect of hydrogel in solid supercapacitor is huge.We have made preliminary attempts in this area.Through random copolymerization,a polymer PS SIM with aniline structure and benzenesulfonic acid group was formed,which was used as a cross-linking agent to prepare PVA/PANI/PSSIM hydrogel electrode.A solid supercapacitor was assembled by using PVA/H2SO4 as a solid electrolyte,PVA/PANI/PSSIM hydrogel as an electrode,and conductive carbon cloth as a collector.Under the action of the crosslinking agent PSSIM,the content of aniline in the PVA/PANI/PSSIM hydrogel is increased,and the doping effect of benzenesulfonic acid improves the conductivity of polyaniline.The prepared solid capacitor has a specific capacitance of 135 F/g,and can still maintain a high capacitance level after benting for many times.