Graphene-polymer composite conductivity in air and water

Highlights: • Exprimental study of the graphene conductivity in water is carried out. • Obtained conductivity temperature dependence is used to estimate the band gap width. • MD simulation is used to find out possible mechanism of the band gap opening in water. • Electric field created by structured water molecules may change conductivity. An experimental study of the graphene conductivity in an aqueous environment is carried out in this study. The presence of a time dependence of the graphene resistivity in water is established. In addition, the characteristic relaxation times of resistivity are determined when graphene is immersed in water and then dried. The resistivity temperature dependence is used to estimate the values of the band gap arising in graphene due to water contact. Based on the analysis of molecular dynamics modeling data, a possible mechanism responsible for the opening of the band gap in graphene is proposed. This mechanism is associated with the inhomogeneous tangential electric field appearance in the plane of the graphene flake, caused by water molecules structured near the graphene surface.