Probing surface microheterogeneity of poly(ether urethanes) in an aqueous environement
Probing surface microheterogeneity of poly(ether urethanes) in an aqueous environement
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DOI：
10.1021/la00059a013
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发表时间：
1991-11
期刊：
影响因子：
3.9
通讯作者：
K. Tingey;J. D. Anbrade
中科院分区：
文献类型：
--
作者：
K. Tingey;J. D. Anbrade
The morphology and microheterogeneous composition of polymeric surfaces partially determines their adsorption and absorption characteristics. The surface structure, often significantly different from that of the bulk, is influenced by the environment, and especially by the interfacial energetics of the surrounding medium. These effects result in dynamic properties with relaxation times that affect the sorptive properties of the materials. Microheterogeneity on surfaces has been shown to have significant effects on the biological interactions between synthetic materials and proteins and/or cells; however, the in situ surface character, which determines the blood compatibility of biomedical copolymers, has only recently come under investigation. The objective of this paper is to present a perspective view of several methods for the characterization of microheterogeneity of dynamic surfaces in an aqueous-or fluid-phase environment. This work focuses on the investigation of the dynamic properties of microheterogeneous biomedical polyurethanes, and on the characterization of these surfaces with novel spectroscopic, surface energetic, and surface imaging techniques. Contact angle, infrared spectroscopy, and inverse chromatography are used to characterize the surface reorientation and heterogeneous microphase nature of polyurethane surfaces. The polyurethanes studied are shown to have a multicomponent surface with detectable hard-segment domains. The chemical structure of the copolymers suggests that the material is composed of domains 150 A in diameter. Evidence of these domains at the surface is presented. We have observed that the concentration of hard-segment surface groups, identified by the aromatic groups in the hard segment, varies as a function of polymer composition. The composition of surface hard segment is minimized with increasing phase purity, indicating the significance of morphology in determining surface composition of these polyurethanes andthe ability of the surface to reorient in response to their environment. We have observed polyurethane surface structural rearrangements induced by hydration of the polymer film. These infrared and contact angle data indicate reorientation of the surface phase structure to enhance the surface concentration of the more polar phase in an aqueous environment. From these studies, structural models of selected polyurethane surfaces havebeen presented and additional analytical methodssensitive to in situ surface morphology have been proposed.
