Mechanism and properties of piezoresistive in rubber-matrix nanocomposites

Advanced materials with excellent piezoresistance sensitivity are attracting more attention due that they can be used as functional materials in pressure sensors. For the researched piezoresistance nanocomposites, we employ canbon nanotubes (CNT) with difference aspect ratios as conducting functional fillers and two kinds of polymers (silicone rubber and thermoplastic elastomer) as polymer matrix, which can produce a great strain at low stress so that finally the nancomposites show outstanding piezoresistance sensitivity. Different to the carbon black (CB)/polymer composites, the CNT/polymer nanocomposites display a positive piezoresistance effect (PPRE), namely the resistance of nanocomposites increases with an increase in pressure stress. Therefore, the mechanism of PPRE is studied in this work by employing the insulating SiO₂ nanoparticles and the electrical conducting CB particles as the second kind of fillers. In addition, the effect of aspect ratio (AR) of CNT on piezoresistivity was explored. A correlation between AR of MWNCNT and piezoresistivity of the corresponding composites was established.