The reason behind this opposite trend in phonon frequency for the G and 2D bands is likely related to the physical origins of each band. Fig. 8 demonstrates the construction and electrical characterisation of a flexible graphene based FET. 13 In Fig. 8a we can see a schematic showing the patterned graphene (1–3 layers) supported by a flexible PDMS substrate as well as a printed ion gel gate. Typically strain occurs as either uniaxial compression or tension however, due to the interactions between the supporting substrate and the graphene shear strain can become the dominant mechanism, which is as a combination of tension and compression perpendicular to each other.