Influence of the second filler on the positive piezoresistance behavior of carbon nanotubes/silicone rubber composites

• This paper discloses the piezoresistivity mechanism of the composites by respectively introducing insulating and conductive particles as the second filler.
• The second filler (SiO2 and CB) serve as “seesaw”, supporting the CNTs and facilitating their orientation in the CNT/SR composites.
• Lower AR endows higher piezoresistivity in the (SiO2–CNT)/SR composites, higher AR is more favorable for the (CB–CNT)/SR composites.

To investigate the influence of the second filler on piezoresistive properties of the composites, silica (SiO2) and carbon black (CB) as the insulating and conductive particles were incorporated into the carbon nanotube (CNT)/silicone rubber (SR) composites. Both SiO2 and CB can serve as “seesaw” to support the CNT, but their effect on the piezoresistivity of CNT/SR composites was remarkably different. Besides, the introduction of SiO2 and CB has a distinct CNT aspect ratio (AR) effect on the piezoresistivity. Lower AR endows higher piezoresistivity in the (SiO2–CNT)/SR composites, but higher AR is more favorable for the (CB–CNT)/SR composites.