Surface analysis of layered polymer brushes

One of the most exciting new features on our recently installed state-of-the-art XPS spectrometer is the capacity for depth-profiling of delicate organic polymeric materials. Preliminary experiments suggest that XPS depth-profiling may provide adequate depth resolution to analyse materials as delicate as polymer brushes with thicknesses of a few tens of nm. In this method, argon gas clusters to remove material layer-by-layer, while the composition and bonding are monitored using XPS. In this project, a series of polymer brushes will be prepared. These will consist of homopolymers of varying thicknesses and copolymers, prepared using atom-transfer radical polymerisation (ATRP),7-8 which gives exceptionally good control of polymer film thickness. Using methods that we recently reported, based on the control of solvent quality as a means to control the depth of penetration of reagents,8-9 brushes will be cross-linked and derivatised9 using a variety of different approaches and the resulting systems used as models to explore the depth resolution of XPS depth-profiling. Nanomechanical measurements will also be made on these systems using AFM, and patterned, layered structures will be characterised using a combination of XPS, imaging SIMS and AFM.