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

• Published in: Composites science and technology 2017-12, Vol.153, p.241-252
• Main Authors: Costa, P., Nunes-Pereira, J., Oliveira, J., Silva, J., Moreira, J. Agostinho, Carabineiro, S.A.C., Buijnsters, J.G., Lanceros-Mendez, S.
• Format: Article
• Language: English
• Subjects: Casting; Deformation mechanisms; Electrical properties; Electrical resistivity; Fillers; Functional composites; Graphene; Heat conductivity; Hopping conduction; Mechanical properties; Percolation; Polymer matrix composites; Polymer-matrix composites (PMCs); Polyvinylidene fluorides; Scanning electron microscopy (SEM); Strain; Vinylidene fluoride
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2017.11.001

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 σ ≈ 5 × 10−11 S/m of pure PVDF to σ ≈ 1 × 10−2 S/m 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≈ 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.