Correlative Theoretical and Experimental Study of the Polycarbonate | X Interfacial Bond Formation (X = AlN, TiN, TiAlN) during Magnetron Sputtering

TL;DR

This study combines ab initio simulations and experimental analysis to understand interfacial bond formation between polycarbonate and various metal nitride thin films, revealing differences in bonding mechanisms and strengths.

Contribution

It introduces a computational-experimental approach to predict and analyze interfacial bonds in organic-inorganic interfaces, specifically polycarbonate with metal nitrides.

Findings

PC | TiAlN has the strongest interface due to high bond density.

PC | TiN shows the weakest interface with fewer strong bonds.

Simulations accurately predict experimental interfacial bonding behaviors.

Abstract

To understand the interfacial bond formation between polycarbonate (PC) and magnetron-sputtered metal nitride thin films, PC | X interfaces (X = AlN, TiN, TiAlN) are comparatively investigated by ab initio simulations as well as X-ray photoelectron spectroscopy. The simulations predict significant differences at the interface, as N and Ti form bonds with all functional groups of the polymer, while Al reacts selectively only with the carbonate group of pristine PC. In good agreement with simulations, experimental data reveal that the PC | AlN and the PC | TiAlN interfaces are mainly defined by interfacial C-N bonds, whereas for PC | TiN, the interface formation is also characterized by numerous C-Ti and (C-O)-Ti bonds. Bond strength calculations combined with the measured interfacial bond density indicate the strongest interface for PC | TiAlN followed by PC | AlN, whereas the weakest is predicted for PC | TiN due to its lower density of strong interfacial C-N bonds. This study shows that the employed computational strategy enables prediction of the interfacial bond formation between PC and metal nitrides and that it is reasonable to assume that the research strategy proposed herein can be readily adapted to other organic | inorganic interfaces.