The role of density on the mechanical and piezoresistive behavior of nanocomposites based on PU/RTV silicone/CNT

Recently, porous piezoresistive sensors have been drawn outstanding attention due to their magnificent electrical properties, outstanding flexibility, and excellent piezoresistivity. Adding a rubbery phase can dramatically enhance the reproducibility of these systems. To this end, a piezoresistive sensor based on polyurethane/RTV silicone rubber/CNT foam was fabricated by a dip-coating process via two different densities of PU sponge, 15 and 20 kg/m3. The purpose of the present study is to investigate the effect of the density of sponges on the sensitivity (GF), and structural recovery of this piezoresistive sensor. In this regard, the CNT particles were first dispersed into a solvent, the silicone rubber was then dissolved in the mixture, and finally, the sponges were immersed. The results of the mechanical test showed that, due to the stronger structure of the foam with higher density, it exhibits more reproductivity than its counterpart with lower density. The change of the specific resistivity of fabricated sensors was investigated. For all composites, two linear regions were reported. The Gauge factor of the sensors through the second region was higher than the first one. In the first and second regimes, the highest sensitivity was considered 1.34 and 3.51 for structures with densities of 15 and 20 kg/m3, respectively.

Keywords:

Room temperature vulcanized silicone rubber (RTV SR) , Polyurethane foam , Piezoresistive , Gauge factor (GF) , Structural recovery.