Investigation of electrical properties of hybrid nanocomposites containing different fillers on pressure sensor applications under different loading

Conductive elastomeric nanocomposites (CEMs) were prepared in two stages to control the precision of pressure sensors. Carbon-based nanofillers such as multi-walled carbon nanotubes (MWCNT) or graphene (GR) were added to the rubber matrix. For Rubber/MWCNT composites, unfunctionalized (U-MWCNT) and –COOH functionalized MWCNT (F-MWCNT) fillers were synthesized. The properties of the CEMs and the synergistic improvements between the fillers and rubber matrix in composites were also investigated. SEM images show that F-MWCNT fillers were dispersed homogeneously in the composites and they interacted with rubber better than other carbon fillers. The piezoresistivity properties of the CEMs before and after compression were determined using the four-probe method by cyclic loading in 1 mm increments between 1.5 mm and 3.5 mm. F-MWCNT filled composites had higher strength than others when they were compressed by 2.5 mm. The F-MWCNT and GR filled nanocomposites possessed the best resistivity for pressure sensors when compressed at 2.5 mm (for F-MWCNT 1.1E + 08 Ω, GR 5.28E + 06 Ω). These nanocomposites are promising pressures sensors for air suspension systems.