High-performance graphene-based carbon nanofiller/polymer composites for piezoresistive sensor applications

Abstract

Poly(vinylidene fluoride) (PVDF) composites with different carbonaceous nanofillers, prepared by solution casting, were studied their chemical, mechanical, electrical and electro-mechanical properties evaluated. Few-layer graphene (FLG) nanoplatelets (G-NPL), graphene oxide (GO) and reduced graphene oxide (rGO) and single-walled carbon nanohorns (SWCNH)) were found to have a strong influence in the overall properties of the composites prepared with up to 5 wt% nanofiller contents. The mechanical strain of carbonaceous nanofillers/PVDF composites decreases from 15% to near 5% of maximum strain. The electrical percolation threshold depends on the nanofiller type, being below 1 wt% for rGO and near 2 wt% for the remaining nanofillers. The electrical conductivity shows a maximum increase of nine orders of magnitude, from sigma approximate to 5 x 10(-11) S/m of pure PVDF to sigma approximate to 1 x 10(-2) Sim for rGO/PVDF composites with 5 wt% nanofillers. The conduction mechanism being related to hopping between the carbonaceous nanofillers for concentrations higher than the percolation threshold. Furthermore, the composites show electro-mechanical properties, except for G-NPL materials, with rGO/PVDF composites with 5 wt% nanofiller content showing higher Gauge factor (GF) values, reaching GF approximate to 11 for deformations between 0.5 and 2 mm in 4-point bending experiments. These results demonstrate the suitability of the composites for strain sensing applications.