Preparation And Property Of Polyvinyl Alcohol-Based Rapid Self-Healing And Conductive Hydrogels

In recent years,conductive hydrogels have been widely applied in the field of flexible electronic devices due to their good electronic properties,tunable mechanical performance and unique biological characteristics.However,hydrogels are easily destroyed during the course of use,which damages the life span of products.Therefore,it is vital to design the hydrogel with synergistic characteristics of rapid self-healing property and conductivity.Here,polyvinyl alcohol-based hydrogels with rapid self-healing performance and conductive capability were prepared.Firstly,GO was partially reduced by DA.Then PVA-PDA-pRGO hydrogel was prepared by adding pRGO into the network formed by PVA and borax.In this system,pRGO provided conductivity(2.7 mS·cm^-1)for hydrogel and the hydrogel was also strengthened by pRGO.Meanwhile,reversible diol borate bonds and hydrogen bonds allowed the hydrogel to display decent self-healing behaviors in mechanical（restore 92.89%of original tensile strength within 60 s）,electrical（restore 96.7%of original resistance within 4.2 s）and rheological recovery experiments without any external stimuli.The catechol groups on PDA can form metal coordinate bonds with Fe³⁺,and the coordination structure is affected by pH.Therefore,we added Fe³⁺to the PVA-PDA-pRGO hydrogel and adjusted the pH of system to form triple coordination structures.The triple coordination structure could be regarded as physical cross-linking points to strengthen hydrogel.In addition,this strengthened hydrogel still had fast self-healing ability.The damaged hydrogel could recover 88.67%of original tensile strength in 60 s without any external assistance.Furthermore,the conductive hydrogels showed strain-sensitivity so the soft strain sensors assembled by designed hydrogels were prepared to observe human movements.