| AVS 54th International Symposium | |
| Applied Surface Science | Wednesday Sessions |
| Session AS+BI+NS-WeA |
| Session: | Fabrication and Characterization of Functional Soft Material Surfaces |
| Presenter: | W.E.S. Unger, Federal Institute for Materials Research and Testing (BAM), Germany |
| Authors: | W.E.S. Unger, Federal Institute for Materials Research and Testing (BAM), Germany A. Lippitz, Federal Institute for Materials Research and Testing (BAM), Germany S. Swaraj, Federal Institute for Materials Research and Testing (BAM), Germany E. Yegen, Federal Institute for Materials Research and Testing (BAM), Germany |
| Correspondent: | Click to Email |
The formation of plasma-polymerized materials made from organic molecules is a technologically highly attractive way to obtain films with unique properties. Surface properties like bio-compatibility, wettability, etc., can be adjusted by tailoring the chemical functionalization. A controlled deposition of those films requires the development of surface analytical procedures which are able to derive useful information on relevant parameters. This can be a hard job for an analyst because plasma-polymerized or plasma-modified materials are extremely complex samples. Their complexity is caused by the co-existence of a relatively high number of chemical species. This leads to a kind of mixture analysis at surfaces but without the possibility of a separation step as it is possible, e.g., by using GC-MS techniques in the analysis of organic mixtures. Relevant parameters for film characterization are primarily (1) qualitative and (2) quantitative determination of functional groups. However there are other important parameters as for instance (3) the cross-linking and branching within the films or even the concentrations of (4) radicals and (5) unsaturated species in the films. It is well known that plasma-polymerized materials may undergo ageing processes. It is assumed that many of them will be initiated by radicals in the films. These radicals are inherently produced by plasma processing. Approaches have to be developed enabling a study of ageing processes on the molecular level including the respective reaction kinetics. So-called "in-situ" techniques of surface chemical analysis are required to investigate the real fresh state of samples. Using a selection of hydroxylated or aminated model plasma polymers and co-polymers it will be demonstrated how analytical approaches based on a combination of photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and x-ray absorption spectroscopy (XAS) may provide solutions for the analytical challenges summarized above.