Self assembled graphene layers on polyurethane foam as a highly pressure sensitive conducting composite

Nano-flakes of graphene can be suitably anchored on a polymer surface to create functionally more active material. Here, a simple method is reported for uniform coating of graphite-oxide onto flexible polyurethane foam and its further conversion to graphene-polyurethane composite. As prepared foam is quite flexible, highly compressible, homogeneous and electrically conducting that exhibits high pressure sensitivity. The material is characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis to study the morphology, chemical interaction between constituent phases and thermal stability respectively. These studies confirm that graphene is strongly immobilized on polyurethane surface by chemical linkage. The influence of applied pressure on electrical conductivity shows that current increases by more than five orders of magnitude for a small change in pressure (just 0.5 atmospheres) yielding pressure sensitivity of 4 x 10(5)/atmosphere. (C) 2013 Elsevier Ltd. All rights reserved.