Preparation And Properties Of Polyaniline-based Conductive Hydrogel And Its Application In Flexible Sensors

Conductive hydrogels show great application potential in flexible wearable sensors.The conductive network structure of hydrogels is deformed under external stimulation,which changes the resistance or conductivity of hydrogels.Conductive hydrogels are usually prepared by combining conductive materials with flexible hydrogels.However,conductive nanomaterials such as carbon nanotubes and graphene oxide tend to aggregate in the process of hydrogel formation,which affects the formation of conductive pathways.Therefore,the electrical properties of conductive hydrogels based on conductive nanomaterials are poor.Conductive polymers such as polyaniline,polypyrrole and polythiophene are preferred for the preparation of conductive hydrogels due to their easy preparation and good electrical conductivity.In this thesis,the conductive hydrogel was prepared by using polyaniline as conductive material and hydrochloric acid as acid dopant.In order to endow the conductive hydrogels with flexibility and conductivity,different flexible materials and polyaniline conductive materials were used to prepare the conductive hydrogels.Specific research contents are as follows:P(AA-co-DMC)/PANI conductive hydrogels were prepared by a two-step aqueous solution method with N,N-methylenebisacrylamide(MBA)as crosslinking agent,azobisisobutamidine hydrochloride(V50)as initiator,acrylic acid(AA)and(DMC)as the matrix and aniline(ANI)as the conductive polymer monomer.The chemical structure and surface morphology of the conductive hydrogel were characterized,and the conductivity,mechanical properties and thermal stability of the conductive hydrogel were studied.The results show that the electrostatic force between zamphoteric ions can increase the mechanical properties of the conductive hydrogel,and the elongation at break is up to 576%and the toughness is up to 0.5 MJ/m3.Zwitterionic ions and polyaniline can effectively improve the electrical conductivity,the electrical conductivity can reach 0.423 S/m.In addition,they can also be used as ionic skin to accurately monitor various movements of the human body,showing a broad application prospect in wearable devices and flexible electronic devices.CMC/PANI conductive material was prepared by using carboxymethyl cellulose(CMC)as stabilizer.In CMC/PANI solution,acrylamide(AM)was used as monomer and F127DA was used as macromolecular crosslinking agent.PAM/CMC/PANI conductive hydrogel with semi-interpenetrating network structure was obtained by free radical polymerization.With the introduction of F127DA,the toughness of hydrogel was improved obviously.At the same time,due to the electrostatic force between CMC and PANI chain,the mechanical properties of the conductive hydrogel are improved.The chemical structure and morphology of the conductive hydrogels were observed by FTIR and SEM,and the effects of ANI and CMC content on the mechanical properties and electrical conductivity of the conductive hydrogels were also studied.When aniline content is 0.2 vol%and CMC content is 1.5 wt%,the conductivity of the hydrogel,elongation at break and toughness is 0.74 S/m,1210%,and 0.8 MJ/m3 respectively.When the strain is 800%,the relative resistivity of the conductive hydrogel can reach 1400%showing good sensitivity...