Morphological influence of carbon nanofillers on the piezoresistive response of carbon nanoparticle/epoxy composites under mechanical load

Journal
European polymer journal  
Volume
85
Start Page
198
End Page
210
Citation
European Polymer Journal (85): 198-210 (2016)
Publisher DOI
10.1016/j.eurpolymj.2016.10.027
Scopus ID
2-s2.0-84992371550
Publisher
Elsevier
In this study, we investigate the piezoresistive response of carbon black and multi walled carbon nanotube/epoxy composites films and bulk specimens. The morphology of the nanocomposites has been influenced by variation of particle geometry, aspect ratio, filler content and AC-field induced alignment of the particles. This allows to understand the influencing parameters so the electrical resistance change (ERC) of the material becomes adjustable. All nanocomposites show a reproducible characteristic ERC vs. strain under quasi-static unidirectional tension, with a resistance increase, a maximum and a subsequent resistance decrease at high strains. Due to the occurring maximum in ERC two resistance values correlate to one strain level. This ambiguity of ERC is unfavourable for sensing purposes. Higher aspect ratios and filler contents shift the maximum to a lower strain level, while the sensitivity is reduced. Alignment of particles leads to a shift of the maximum to a higher strain level, a linear ERC and a gauge factor of about six, but reduces the conductivity. In the composites films the alignment of particles in load direction enhances the strain sensing capabilities.