An XPS and SIMS analysis of biodegradable biomedical polyesters

The polymer surface compositions of some polyesters of importance in biomaterial science and advanced drug delivery have been examined by x‐ray photoelectron spectroscopy (XPS) and static secondary ion mass spectrometry (SSIMS). The XPS results show good quantitative stoichiometric correlation with the known chemical composition of the polyesters. The SIMS spectra show systematic fragmentation patterns in both positive and negative ion modes for the series of structurally related polymers. Evidence for the presence of radical cation formation in SIMS is presented. Comparison between the SIMS spectra of poly‐glycolic acid and poly‐lactic acid and the pyrolysis mass spectra of these polymers are made, and conclusions drawn on the different mechanisms of fragmentation. The combined application of SSIMS and XPS is shown to give a highly detailed analysis of these polyesters.