This study examines the piezoresistive behavior of polymer-conducting filler composites. Piezoresistive composites of Poly(dimethyl-siloxane)-Multiwall Carbon Nanotube (PDMS-MWNT) were prepared using a direct mixing approach. The dispersion and the electrical conductivity of the composites were characterized at various MWNT compositions. The piezoresistive behavior under compression was measured using an Instron Universal Tester/Digital Sourcemeter combination. Negative piezoresistive behavior was observed signifying a reducing mean inter-particulate distance in the composites. Moreover, the sensitivities increased at two compositional values of 3 and 5 wt% MWNT in PDMS, which was associated with the state of MWNT dispersion observed. Tensile piezoresistive behavior of the PDMS-MWNT adhered on a fabric substrate was also characterized. Positive piezoresistive values, indicating increasing inter-particulate distance, were observed. Significant challenges in the implementation of PDMS-MWNT as sensory materials in electronic-textile applications were observed as a result of this study and have been discussed.
Anomalous electrical conductivity and percolation in carbon nanotube composites
