Quantum chemical calculation of electron transfer at metal/polymer interfaces

Calculation of contact charging at metal/polymer interfaces were performed by a quantum chemical method (DV-Xa). In the calculation, model clusters with dangling bonds were used. The model clusters showed surface states in the density of states (DOS), the electron transfer occurred at the contact interfaces between polymer and Al. Then, 0.3 nm was a reasonable value as the contact distance in the present simulation. Contact electrifications between PTFE and six metals, such as Pt, Au, Cu, Al, Pb and Ca were simulated. The charge transferred from the metal to PTFE depended on the work function of the metals, and had a gap in range of 4.25–4.28 eV. According to the gap of metals were classified into two groups. If Fermi level of a metal is lower than the lowest unoccupied molecular orbital (LUMO) level of PTFE, the electrons of the metal transfer to the surface state (interface state). Electrons in the other metals with a higher Fermi level move into the conduction band of PTFE.