THE ANALYSIS OF THE SURFACE CHEMICAL-STRUCTURE OF BIOMEDICAL ALIPHATIC POLYANHYDRIDES USING XPS AND TOF-SIMS

The surface chemical structure of a range of aliphatic polyanhydride films has been examined using XPS and ToF-SIMS. The XPS data confirms the purity of the surface, and the experimental surface elemental ratios are in good general agreement with the known stoichiometry of the polyanhydrides. The ToF-SIMS spectra of the polyanhydrides are shown to be significantly different. The SIMS data conforms to a systematic fragmentation, in both negative- and positive-ion SSIMS spectra, occurring throughout the entire series of polyanhydrides examined. Radical cations are observed in the positive-ion spectra. These results are discussed in terms of the general fragmentation patterns observed in the SIMS analysis of polymers. The combined use of ToF-SIMS and XPS is shown to provide a detailed insight into the interfacial chemical structure of these polyanhydrides.