Silicone rubber/graphite nanosheet electrically conducting nanocomposite with a low percolation threshold

A novel electrically conductive nanocomposite was successfully fabricated by dispersing homogeneously conductive graphite nanosheets (GN) in an insulating silicone rubber (SR) matrix. GN were prepared by powdering expanded graphite with sonication in aqueous alcoholic solution. The particular geometry of GN 30-80 nm in thickness with high aspect ratio contributes to the advantage of forming the conducting network, so that the percolation threshold of SR/GN nanocomposite is about 0.009, much lower than that of composites with conventional graphite. The SR/GN nanocomposite presents a remarkable piezoresistive behavior under much low pressure, related to the low elastic modulus of the composite. The elastic modulus of the nanocomposite with various GN content and at the different speed of compression was discussed.