Elastic properties of graphene oxide films and changes due to gas phase adsorption.

This work deals with the characterization of Graphene Oxide (GO) films for application to acoustic gas sensors. The preparation of the GO dispersion and its deposition on the surface of SAW and BAW devices is reported. Measurements of the frequency dependence of the resistance and reactance for the different electro-acoustic structures tested, in the presence of dry air (reference) and of concentrations of different gases or vapors, allowed us to evaluate the elastic moduli and their dependence on the adsorbed gas. A negligible response to H-2, CO, CH4, NO and O-2 has been demonstrated for GO, while exposure to humidity gives rise to high responses. The elastic modules of the film are 3 orders of value smaller than those of traditional sorbent materials, while the changes produced in the modules by humid air are 1 order of value larger.