Evaluation of the piezoresistive behavior of multifunctional nanocomposites thin films

The piezoresistive properties of thin films based on carbon nanotubes dispersed in conductive polymer were investigated. Conductive multiwalled carbon nanotubes / Poly (3,4-ethylenedioxythiophene) polymerized with poly(4-styrenesulfonate) (PEDOT:PSS) films were prepared and deposited on flexible polymer substrates (Kapton HN, 250 μm) by drop casting and the aqueous dispersions with different amounts of MWCNTs in PEDOT:PSS were prepared at different sonication times. The influences of the MWCNT load on the film properties such as electrical conductivity; strain sensitivity and hysteresis were investigated. Negative resistance coefficient was observed when the films are subjected to a force from 10 N to 110 N. Furthermore, it was observed that at low amounts of MWCNTs dispersed in PEDOT:PSS with sonication time of 15 min have better strain sensitivity then pure PEDOT:PSS and other prepared thin film composites. Moreover, the strain sensitivity was found to be strongly dependent on the MWCNT concentration. In general, MWCNT/PEDOT:PSS films have potential as a highly linear strain sensitive material.