Hemocompatibility properties of a polymer surface treated in plasma containing sulfur

Polymer polyethylene terephthalate was treated in plasmas containing sulfur to incorporate different sulfur functional groups and improve its hemocompatibility properties. Plasma was created either by SO 2 , H 2 S or an H 2 S/O 2 mixture. Sequential treatments in H 2 S and O 2 plasmas were also used. The surface of the treated samples was analyzed using X‐ray photoelectron spectroscopy, and surface hemocompatibility was tested by investigating platelet adhesion. While SO 2 plasma caused functionalization of the surface with –SO 3 and –SO 4 functional groups, H 2 S plasma caused functionalization with non‐oxidized –SH 2 sulfur groups, as well as sulfur deposition on the polymer surface. Addition of oxygen to the H 2 S gas caused a significant decrease in the amount of sulfur on the polymer surface and only minor sulfur oxidation. This observation led to the conclusion that added oxygen removed/prevented sulfur deposition on the polymer surface. Enhanced results were obtained by a sequential treatment in H 2 S and then O 2 plasma, where oxidation of sulfur and formation of –SO and –SO 2 functional groups were observed. The O 2 plasma exposure had to be short enough to prevent the unwanted removal of sulfur from the surface. High platelet adhesion was observed for all plasma‐treated surfaces. Copyright © 2016 John Wiley & Sons, Ltd.