Efficacy of graphitic allotrope’s surface area in silicone rubber based composites for reverse piezo-electric actuation: Nano effect

Abstract

Filler surface areas importantly determine the properties of rubber composites. In this study, the reverse piezo-electric actuation efficacies of three graphitic allotropes were studied in room temperature vulcanized silicone rubber (RTV-SR) based composites. The three fillers examined were graphite, nanographite, and graphene. Specific surface areas were determined using the Brunauer–Emmett–Teller (BET) method in a nitrogen atmosphere. BET testing showed graphite, nanographite, and graphene had surface areas of 30, 110, and 650 m2/g respectively. Mechanical properties showed that fillers with greater BET surface areas had higher compressive moduli, tensile strengths, fracture strains, and tensile moduli. Similarly, actuation measurements obtained at 10 kV showed that composites containing graphene produced significantly greater actuation displacements than those containing nanographite or graphite. The figure of merit showed filler BET surface areas played a key role in determining the mechanical and actuation properties of composites. For example, as the surface area increases, the properties and actuation displacement increases exponentially. To sum-up, graphene filled silicone rubber composites exhibited better mechanical properties and much better actuation displacements than graphite or nanographite filled composites.