Effect of polydimethylsiloxane strain on its contact electrification characteristic: a first-principles investigation

Abstract Material strain is one of the factors affecting contact electrification. Previous works have investigated the influence of polymer strain on contact electrification from the perspective of material transfer by means of experimental methods. However, the detailed electron transfer mechanism, which is the most fundamental form of contact electrification mechanism, is still unclear. In this work, the effect and its mechanism of polydimethylsiloxane (PDMS) tensile strain on contact electrification with polytetrafluoroethylene (PTFE) are investigated via first-principles calculations. The results show that the number of electrons transferred from the PDMS to the PTFE increases with the stretched ratio. In addition, the possibility of breakage on the PDMS main chain caused by tensile strain is considered. The result shows that the total number of transferred electrons from the broken fragments is much less than that of the original PDMS molecule. Moreover, the fragment of PDMS molecules with the oxygen dangling bond can even obtain electrons from the PTFE molecule. This work can provide a theoretical basis for understanding the influence mechanism of polymer strain on contact electrification from the perspective of electron transfer.