a modified medical device substrate surface designed to improve adhesion of biomimetic surfactants to the medical device surface , thus reducing the risk of thrombosis is described . the surface modification is accomplished through either an application of a tie layer of a hydrophobic material on the substrate surface intermediate the biomimetic coating or through incorporation of a hydrophobic dopant in the polymeric substrate prior to extrusion or molding . either method creates a hydrophobically modified surface that enhances the biomimetic surfactant bonding strength .