Raman study of interfacial load transfer in graphene nanocomposites

We tracked the strain-sensitive characteristic Raman G-band shift of graphene platelets in polydimethyl-siloxane (PDMS) nanocomposites revealing the filler-to-matrix interactions. We obtained large debonding strains of similar to 7% for graphene in PDMS, with the peak shift rate with strain being similar to 2.4 cm(-1)/composite strain % in comparison to single-walled carbon nanotube composites, where a relatively low rate of similar to 0.1 cm(-1)/composite strain % was obtained, suggesting enhanced load-transfer effectiveness for graphene. A surprising observation was that for large strains (>1.5%) the graphene fillers went into compression under uniaxial tensile deformation and vice versa. We propose that this effect is related to the high mobility of the PDMS chains at room temperature. (C) 2011 American Institute of Physics. [doi:10.1063/1.3552685]