Although polyetherurethanes (PEU's), because of their excellent mechanical properties, are being used with increasing frequency in both clinical medicine and in biomedical research, significant problems including poor blood compatibility, low biostability and a tendency towards calcification remain largely unsolved. This proposal will address these problems. Two hypotheses are offered: (1) that polyurethanes with hydrocarbon, silicone or fluorocarbon moieties localized at their surfaces may be more blood compatible, and may exhibit a reduced tendency to biodegrade and calcify, and (2) the heterogeneity, but that this heterogeneity can be reduced. New polyurethanes will be synthesized that are expected to have surface- localized structures that are resistant to degradation and appropriate for low platelet reactivity. We will analyze new polyurethanes and existing biomedically important PEU's (before and after simulated biodegradation) by state of the art methods including ESCA, SIMS, FTIR, near infrared spectroscopy, gel permeation chromatography and efficiently analyzing this large mass of data with two objectives for this analysis in mind: pattern recognition to detect and quantify subtle changes and degradation resistance and blood compatibility.