Bond Formation at Polycarbonate | X Interfaces (X = Al2O3, TiO2, TiAlO2) Studied by Theory and Experiments

Interfacial bond formation during sputter deposition of metal-oxide thin films onto polycarbonate (PC) is investigated by ab initio molecular dynamics simulations and X-ray photoelectron spectroscopy (XPS) analysis of PC|X interfaces (X = Al2O3, TiO2, TiAlO2). Generally, the predicted bond formation is consistent with the experimental data. For all three interfaces, the majority of bonds identified by XPS are (C & horbar;O)& horbar;metal bonds, whereas C & horbar;metal bonds are the minority. Compared to the PC|Al(2)O(3 )interface, the PC|TiO(2 )and PC|TiAlO(2 )interfaces exhibit a reduction in the measured interfacial bond density by 75 and similar to 65%, respectively. Multiplying the predicted bond strength with the corresponding experimentally determined interfacial bond density shows that Al(2)O(3 )exhibits the strongest interface with PC, while TiO(2 )and TiAlO(2 )exhibit similar to 70 and similar to 60% weaker interfaces, respectively. This can be understood by considering the complex interplay between the metal-oxide composition, the bond strength, and the population of bonds formed across the interface.