Synthesis and Characterization of Zwitterionic Organogels Based on Schiff Base Chemistry

Poly(sulfobetaine)s and poly(carboxybetaine)s have been extensively studied for their zwitterionic and biocompatible nature. The specific features that make such zwitterionic structures technologically important are their chemical structure, a straight forward synthetic route, high ionic contents with interesting dilute solution, and solid state properties. The objective of this work is to synthesize novel zwitterionic polymers having gel characteristics. Here, p-phenylene diamine/melamine react as nucleophiles with glutaraldehyde to produce poly(schiff base)s. in the subsequent step, the poly(sulfobetaine)s and poly(carboxybetaine)s were produced on treatment with 1,3-propane sultone/gamma-butyrolactone. Hence, a catalyst free facile approach to novel zwitterionic polymers was obtained. The polymers were characterized by elemental analyses, FTIR, XRD analyses, SEM, pH metric titrations, conductometric titrations, and thermal analyses (TGA/DTA). The polymeric samples carry the gel characteristics, showing lamellar structure with porous network. XRD pattern shows Bragg peaks indicative of superstructures. Thermal analysis indicates the Hoffman elimination of 13 hydrogen and subsequent release of sulfopropyl/carboxybutyl group. One of the gel polymers shows fluorescence also. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 2821-2832, 2010