Piezoresistive effect of a carbon nanotube silicone-matrix composite

A carbon nanotube silicone-matrix composite is fabricated into a specimen with two current-electrodes and two voltage-electrodes. The specimen is sealed transversely and the four-wire-method is used to measure the piezoresistivity of the composite during compression. The electrical resistance and the resistivity of the composite increase with the increase of the absolute value of the strain during compression. The absolute value of the gage factor decreases with the increase of the carbon nanotube content. By analyzing the changes in the effective conductive path (ECP), a piezoresistive mathematical model is established. The resistance of a tunneling film (i.e. the silicone film between the adjacent carbon nanotubes where the tunneling effect occurs) attenuates with the increase of the absolute value of the strain during compression. The attenuating rate decreases with the increase of the carbon nanotube content. The ratio of the number of the tunneling films in each ECP to the number of ECPs in the composite decreases with the increase of the carbon nanotube content and increases with the increase of the absolute value of the strain during compression. (C) 2014 Elsevier Ltd. All rights reserved.