Synthesis of highly conductive hydrogel with high strength and super toughness

The manufacture of high performance flexible electronic materials remains a huge challenge. Herein, a facile strategy was developed for the preparation of conductive hydrogel with high strength and super toughness using green biomass lignin and biodegradable poly(vinyl alcohol) (PVA) as raw materials. The enzymatic hydrolysis lignin (DEL) was introduced into the PVA hydrogel to form the nanophase separation structure and promote the adsorption of silver ions, which significantly contributed to the improvements in mechanical and conductive properties of the composite hydrogel. The silver ions in the hydrogel were reduced to generate the silver nanoparticles (AgNPs) by immersing in the green reducing agent of sodium citrate solution. The silver nanoparticles in the hydrogel network significantly enhanced the hydrogel, endowing the composite hydrogel Ag0@DEL with particularly large toughness of 78.1 MJ/m3, powerful tensile strength up to 13.3 MPa and high strain at break up to 1220%. The composite hydrogel Ag0@DEL also exhibited good electrical conductivity of about 1.0 S/m and performed high strain sensitivity and stable response to the deformation of stretching, compression and twist.