Tuning micro-wrinkled graphene films for stretchable conductors of controllable electrical conductivity
CF Feng and ZF Yi and LF Dumee and FH She and Z Peng and WM Gao and LX Kong, CARBON, 139, 672-679 (2018).
Accurately controlling the electrical conductivity of wrinkled graphene or graphene oxide (GO) structures is challenging due to the complex sheet-to-sheet interactions and hierarchical interactions at the nanoscale. In this paper, wrinkled GO films with predictable electrical conductivity by precisely controlling thickness ranging from 0.69 to 1.68 mu m were fabricated with a thermal process where a GO-coated polystyrene shrink film was isotropically shrunk. Theoretical and experimental results show consistent dependence of the wrinkle wavelength on the GO film thickness. Beyond a certain thickness threshold, poorly wrinkled structures were formed as GO sheets started delaminating from the shrink films. A coarse-grain molecule model based on molecular dynamic simulation principles was developed to understand the formation of the wrinkles, and establish a relationship between GO thickness and the wrinkle wavelength generated. The electrical resistance was found to decrease when the thickness of the GO films increases. The formed composite film can maintain a stable electrical conductivity after experiencing up to 1000 stretching-release cycles under 10% strain. With controllable electrical conductivity, the reported composites can offer potential applications as a strain sensor with tuneable sensing range and high durability. (C) 2018 Elsevier Ltd. All rights reserved.
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