a comb - like surfactant polymer for changing the surface properties of biomaterials is described . the surfactant polymer comprises a polymeric backbone of repeating monomeric units having functional groups for chemically attaching to side chains , a plurality of hydrophobic side chains attached to the backbone via the functional groups and a plurality of hydrophilic side chains chemically attached via functional groups to the polymeric backbone . the hydrophilic side chains providing anti - thrombogenic properties to the surfactant . an antimicrobial agent selectively attached to some hydrophilic side chains thereby providing additional antimicrobial properties to the surfactant . the surfactant polymer may be applied to the surface of medical devices to reduce the surfaces thrombogenicity and decrease the number of microorganisms on the surface .