Stretchable supramolecular hydrogel with instantaneous self-healing for electromagnetic interference shielding control and sensing

Conductive hydrogels possess instantaneous self-healing and adhesive properties have generated great excitement in the fields of sensing and electromagnetic interference (EMI) shielding. In this study, we ingeniously designed hydrogel-based soft materials with high conductivity by using poly(vinyl alcohol) (PVA), positively charged Ti₃C₂T_x MXene and thioctic acid (TA) as source materials. Through concentration-induced ring-opening polymerization of TA monomers in an aqueous solution of potassium hydroxide (KOH), supramolecular poly(potassium thioctate) (poly(PT)) was obtained. Then, the multifunctional poly(PT)/PVA/p-MXene hydrogel with exceptional stretchability, substrate-adhesion and self-healing capability was achieved through abundant dynamic bonds, including disulfide bonds, hydrogen bonds, coordination bonds and electrostatic interactions. The hydrophobic main chains within poly(PT) provide robust protection against the oxidative degradation of MXene. This hydrogel shows outstanding strain sensing and extraordinary EMI shielding effectiveness (SE) of 48.56 dB caused by the inner structure, conductivity, and water content. Interestingly, the EMI SE can be regulated by reabsorbing moisture from the air, thereby enabling the reuse of dried hydrogel. Furthermore, the EMI SE can be dynamically modulated through controlled deformations, confirming the potential application for electromagnetic waves (EMWs) sensing. This innovative approach not only simplifies the fabrication of multifunctional materials but also expands the applications of adhesive hydrogels with conductivity.