title: An Ionic Liquid as Interface Linker for Tuning Piezoresistive Sensitivity and Toughness in Poly(vinylidene fluoride)/Carbon Nanotube Composites.
abstract: Conductive polymer nanocomposites (CPNCs) have emerged as potential alternatives for metallic foil sensors and semiconductor strain gauges. The simultaneous achievement of high piezoresistive sensitivity and large strain ranges for CPNCs currently presents a great challenge and solving this challenge may extend the applications of CPNCs with self-diagnosis capabilities to many structural health-monitoring (SHM) systems. This paper reports a facile strategy for fabricating highly piezoresistive and tough poly(vinylidene fluoride) (PVDF) based CPNCs by tuning the interactions between the polymer matrix and multiwalled carbon nanotubes (CNT) using an ionic liquid (IL) as an interface linker/modifier. As a result, the presence of IL achieves homogeneous dispersion of CNTs in PVDF but causes a reduced number of CNT-CNT ohmic contacts with higher electrical contact resistance. According to the lower initial resistivity, piezoresistive sensitivity is greatly improved, and the gauge factor (GF) varies from 7 to 60 upon the addition of IL. It is also shown that IL tunes PVDF-CNT interfacial bonding and, as an effective interface linker/modifier, achieves significantly improved sensing strain ranges (increased from ca. 6 to 21%) and toughness (elongation at break increases from 6 to 130%) of CPNCs. These results substantially advance the understanding of the missing relationship between polymer-filler interface interactions and piezoresistive properties and have important implications for future studies of tuning polymer-filler interface bonding properties and piezoresistive sensitivity.
authors.affiliation: Leibniz Institute of Polymer Research Dresden (IPF) , Hohe Strasse 6, 01069 Dresden Germany.|Organic Chemistry of Polymers, Technische Universität Dresden , 01062 Dresden, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Ke
authors.affiliation: Leibniz Institute of Polymer Research Dresden (IPF) , Hohe Strasse 6, 01069 Dresden Germany.
authors.forename: Petra
authors.identifier: http://orcid.org/0000-0001-6392-7880
authors.initials: P
authors.lastname: Pötschke
authors.affiliation: Leibniz Institute of Polymer Research Dresden (IPF) , Hohe Strasse 6, 01069 Dresden Germany.
authors.forename: Shanglin
authors.initials: S
authors.lastname: Gao
authors.affiliation: Leibniz Institute of Polymer Research Dresden (IPF) , Hohe Strasse 6, 01069 Dresden Germany.|Organic Chemistry of Polymers, Technische Universität Dresden , 01062 Dresden, Germany.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Voit
keywords: carbon nanotubes (CNTs); interface interactions; ionic liquid; piezoresistivity; poly(vinylidene fluoride) (PVDF)