title: Application of Auger electron spectroscopy for surface chemical analysis of Avcothane.
abstract: The effect of the exposure to air or to the substrate during the solvent casting process on the surface chemical composition of Avcothane, a blood compatible biomaterial, was studied by employing Auger electron spectroscopy. The surface layer of 10-15A thickness was analyzed without sputtering, but for the studies probing a deeper layer, argon ion sputtering at a low enough voltage to prevent artifacts was utilized. It is found that the air facing surface which is the blood contact surface contains a greater amount of silicone polymer and a much lower amount of the urethane hard segment in the first 10-15A-deep layer than in the comparably thick layer of the substrate surface. However, the depth-composition profile obtained by sputtering indicate that, probably at a deeper depth, the chemical compositions in terms of silicone polymer and hard segment is comparable both in the air side and the substrate side.
mesh_terms: D002244:Carbon / Q000032:analysis; D004129:Dimethylpolysiloxanes / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis; D010100:Oxygen / Q000032:analysis; D011140:Polyurethanes / Q000032:analysis*; D012825:Silicon / Q000032:analysis; D012828:Silicones / Q000032:analysis*; D013057:Spectrum Analysis / Q000379:methods; D013499:Surface Properties
chemical_list: D004129:Dimethylpolysiloxanes; D011140:Polyurethanes; D012828:Silicones; D002244:Carbon; D009584:Nitrogen; D010100:Oxygen; D012825:Silicon