The relationship between end-group concentrations and stability of spin-coated thin polymer films investigated by ToF-SIMS depth profiling

Stable and unstable spin-coated polymer films were prepared using various solvents and substrates. The relationship between polymer end-group concentrations and stability of spin-coated polymer films was revealed by time-of-flight secondary ion mass spectrometry depth profiling. A high concentration of bromine end groups at the interface between the polymer and the substrate helped to prevent the dewetting of films. In contrast, the bromine end groups were found to be more evenly distributed in unstable thin films. The extent to which the bromine end groups segregate to the interface depended on the competitive interactions between the polymer, the solvent and the substrate. Stronger polymer-solvent and solvent-substrate interactions prevented the segregation of the bromine end groups to the interface, resulting in unstable polymer films. Copyright (c) 2013 John Wiley & Sons, Ltd.