Effects of material strain on triboelectric charging: Influence of material properties

We address electrostatic charging of unstrained and strained latex rubber sheets contacted with a series of materials: polytetrafluoroethylene (PTFE), polyurethane (PU) and stainless steel (SS). For PTFE, strain causes a reversal in the direction of charge transfer. For PU, the direction of charge transfer is reversed after repeated contacts due to material transfer, and strain increases the number of contacts needed for this reversal. For SS, strain reduces the frequency of electrical discharges occurring. These effects may be explained by strain either changing material properties relevant to triboelectric charging, or changing the nature of contact between the surfaces.