Microscopic features of methacrylate polymers with zwitterionic pendant groups determined by various techniques

The objective of this work was to determine microscopic structural features of three methacrylate polymers with different numbers of diethylene glycol residues and zwitterionic pendant groups. X-ray diffraction, electron microscopy, and scanning probe microscopy techniques were employed. X-ray data led to the adoption of a model made up of molecular aggregates forming lamellar domains, establishing in this way ordered characteristics of these kinds of polymers. Scanning electron microscopy images provided evidence of the occurrence of a lamellar structure forming the morphology of the polymers. This was corroborated by atomic force microscopy experiments. Transmission electron microscopy revealed that the lamellar aggregates conformed into clusters immersed in a polymeric matrix. From phase-contrast images, information on the homogeneity of the composition at a molecular surface level was obtained. Then, the techniques provided evidence of the lamellar domain characteristics of the studied sulfobetaines. The crystallinity was a function of the number of ethoxy groups because as this number increased, the crystallinity became lower. (c) 2005 Wiley Periodicals, Inc.