Highly aligned and porous reduced graphene oxide structures and their application for stretchable conductors

Developing materials that can absorb large amounts of strain without fracture or significant degradation in their electronic properties is essential for the realization of stretchable electronics. Here, stretchable conductors made from reduced graphene oxide/polydimethylsiloxane (r-GO/PDMS) composite were fabricated to achieve stable resistance changes under uniaxial stretching. By controlling the weight fraction of GO in water, highly aligned and porous GO structure was obtained over 0.5 wt% of GO solution. After thermal and chemical reduction of GO to r-GO film, PDMS was infiltrated into pores of the film to make free-standing and elastic composites. Electrical percolation of r-GO in the composite was achieved at the r-GO concentration over 0.3 wt% along with improvement of electrical conductivity. However, highly aligned r-GO/PDMS composite only exhibited notable suppression of resistance change under the large deformation of 100% strain. The resistance change of 0.3 wt% r-GO/PDMS composites at 100% strain was over 7 times higher than that of 0.7 wt% r-GO/PDMS composites, exhibiting the dramatic effect of r-GO alignments. Even after repeated stretching/releasing cycles, the variation in resistance from 0 to 70% of strain was stable. The stretchable conductor based on the aligned r-GO/PDMS composite was successfully applied as a resistive strain sensor. (C) 2019 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.