Development of a shear strengthening conductive hydrogel for impact protection and distress signal emission

Abstract

This study presents the development of a novel hydrogel that combines shear strengthening behavior with electrical conductivity, providing dual functionalities for impact protection and distress signal emission in response to collisions. To address the challenges of cold flow and creep typically associated with conventional shear strengthening gels, a composite hydrogel was formulated using sodium alginate (SA), ethylene glycol (EG), and carbonylated multi-walled carbon nanotubes (MWCNT) within a sodium borate (SB) cross-linked polyvinyl alcohol (PVA) matrix. The incorporation of ethylene glycol not only addressed moisture evaporation but also enhanced the relative shear strengthening effect (RSTe) by an impressive 3301 %. Meanwhile, the inclusion of MWCNT provided hydrogel with a measured electrical conductivity of 7.05 mS/m. The resultant material demonstrated remarkable creep resistance and mechanical properties, achieving an energy absorption rate of up to 90 % and a buffer time of 1.23 ms. Additionally, this hydrogel has potential applications as electronic skin, enabling functionalities such as signal recognition, transmission, and early warning systems. By merging the sensing capabilities of hydrogels with their impact resistance, this innovative material paves the way for advanced intelligent protection applications.