Macromol. Chem. Phys. zyxwvu 195,2663 zyxwvu - 2675 zyxwv (1994) zyxwv 2663 z Surface studies on copolymers having pendant monosaccharides Katsuhiko Nakamae? Takashi Miyata, Norihito Ootsuki Faculty of Engineering, Kobe University, Rokko, Nada, Kobe 657 Masakazu Okumura, Keisuke Kinomura Nippon Fine Chemical Co., Ltd., 1-1, 5, Umei, Takasago, Hyogo 676 (Received: October 20, 1993) SUMMARY Copolymers having pendant monosaccharide groups were synthesized by copolymerizing 2-(glucosy1oxy)ethyl methacrylate (GEMA, l), with methyl methacrylate (MMA) or styrene (St). The surface characteristics of the copolymer films were investigated by means of contact angle measurements, X-ray photoelectron spectroscopy (XPS), and protein adsorption. The surface free energy of the GEMA/St copolymer films was constant in the range of a GEMA content from 10 mol-To to 60 mol-To. Insertion of GEMA of over 60 mol-To, however, caused an increase of the surface free energy of the copolymer films. The surface composition determined by means of XPS supported the result from surface free energy measurements. There was a significant difference between the GEMA/St and GEMA/MMA copolymer films in the effect of the GEMA content on the surface characteristics of the films. The differences could be explained on the basis of the sequence of monomeric units in each copolymer. Immersing the copolymer films in hot water made the copolymer surface more hydrophilic. This is because each component migrates to the surface or the bulk in order to minimize the surface free energy of the copolymer films. The introduction of GEMA to the copolymer suppressed fibrinogen adsorption onto the copolymer films. Introduction The surface characteristics of polymers are important in the development of bio- materials'). When a polymer is used as a biomaterial, good biocompatibility is required. Such biocompatibility of a polymer is dependent upon physicochemical and biological interactions between the polymer surface and biomolecules. Therefore, the polymer surface must be precisely characterized to reveal such interactions for the development of biocompatible materials. A great deal of effort has also been made on designing and controlling the polymer surface by surface modifications such as plasma treatments2, 3). The surface composition of a polymer is generally different from its bulk composi- ti~n~*~-"). In the copolymer consisting of different components, the hydrophobic component that has a lower surface free energy is preferentially localized at the polymer surface. We have characterized the surface of ethylenehinyl alcohol copolymer (EVA) membranes prepared under various conditions using X-ray photoelectron spectroscopy (XPS)'*Z'~). The surface compositions of the EVA membranes were influenced by the preparation conditions. When the membrane was exposed to hydrophobic environ- ments, the membrane surface was enriched in the ethylene component. Since the z 0 1994, Hiithig & Wepf Verlag, Zug CCC 1022-1352/94/$08.00