Electrically conducting porous hydrogels by a self-assembled percolating pristine graphene network.

Abstract

This study introduces a method for synthesizing electrically conductive hydrogels by incorporating a self-assembled, percolating graphene network. Our approach differs from previous approaches in two crucial aspects: using pristine graphene rather than graphene oxide and self-assembling the percolation network rather than creating random networks by blending. We use pristine graphene at an oil-water interface to stabilize a water-in-oil emulsion, successfully creating hydrogel foams with conductivities up to 15 mS m^-1 and tunable porosity. Our approach avoids the need for the conductivity-degrading oxidation process to form GO and decreases the amount of graphitic filler needed for percolation, leading to superior mechanical properties. The concentration of monomer and graphite in the emulsion was optimized to control the cell size, stability, and swelling behavior of the final hydrogels, offering versatility in structure and functionality. Electrical conductivity and thermogravimetric analysis (TGA) confirmed the stability and conductive properties imparted by the graphene network. This method demonstrates a cost-effective route to conductive hydrogels, making them promising candidates for applications in sensors, energy storage, bioelectronics, and other advanced technologies.