The dependence of the graphene electrical resistance on mechanical deformation

In this work, the piezoresistive properties of polymer-graphene composites were investigated. The electrical resistance of these samples ranged from 693 to 1277 Ohm/sq for single-layer graphene coating, and from 477 to 1096 Ohm/sq for multilayer coating. It was shown that with a tensile strain of 4%, the maximum gauge factor was 100. For bending with a radius of curvature of 70 mm, which corresponds to a stretch of 0.75%, the maximum gauge factor was 34. It is shown that samples with a single-layer graphene coating are more resistant to deformation processes their electrical resistance changes less than in samples with a multilayer graphene coating. Such a phenomenon can be associated with an increased concentration of defects and imperfections in graphene structures, which, in the case of a multilayer coating, leads to lower strength of the entire structure and much more destructive consequences in tension. A multilayer coating can have a heterogeneous structure: individual multilayer islands can be connected by single-layer sections. The gap between the latter leads to a significant drop in the electrical resistance of the entire sample.