Construction of multifunctional films based on graphene-TiO2 composite materials for strain sensing and photodegradation

We develop a simple approach to fabricate graphene-TiO2 films both on rigid and flexible substrates by the spray coating technique. A drastic synergetic effect was found simply by mixing graphene with TiO2. The composite films were conductive and showed enhanced photocatalytic activities. More significantly, the graphene-TiO2 composite films which could sustain a large tensile deformation (5% strain) demonstrated high sensitivity to mechanical strain with tunable gauge factors (GF) of 14-35. The remarkable performance could be attributed to the combination of photocatalytic performance derived from TiO2 nanoparticles and the electrical and mechanical properties of graphene nanosheets. Based on the observed results, a plausible mechanism was proposed. Overall, this work could provide new insights into the research of the graphene-TiO2 composite materials and facilitate their application in a broad range.