Abstract: The present invention relates to novel polymeric compositions of matter and their use. Said polymeric compositions of matter are surface active endgroup-containing polymers that comprise a linear base polymer having covalently bonded surface active endgroups of a nature and present in an amount such that said polymers have a surface or interfacial tension that differs by at least 1 dyne/cm from the surface or interfacial tension of an otherwise identical polymer that does not contain said covalently bonded surface active endgroups. The novel linear polymers according to the present invention are particularly suitable for use in the manufacture of medical devices, and especially of medical devices intended to be used in contact with bodily fluids such as blood. Examples of such medical devices include catheters and artificial hearts.