Electronic states of excess electrons in polyethylene

We compare and contrast preliminary semiclassical results for the electronic states associated with excess electrons in explicit molecular models of crystalline polyethylene and an alkane crystal C₂₇H₅₆. In addition we consider the low energy states in models of amorphous polyethylene and in voids in amorphous polyethylene. From our results it is clear that alkane crystals are not representative of crystalline polyethylene although they are often so considered. In amorphous polyethylene the ground state is estimated to be at -0.27 ± 0.1 eV with the electron localised on a nanometre scale in regions of relatively low density. A nanometer void in the amorphous region lowers the ground state to -0.45 ± 0.1 eV. With respect to realistic models of the crystalline regions of polyethylene such states constitute electron traps of the order of 1.0 eV and are therefore likely to play an important role in determining electron transport in polyethylene.