Fundamental studies of novel inorganic–organic zwitterionic hybrids. 1. Preparation and characterizations of hybrid zwitterionic polymers

Four types of novel inorganic–organic hybrid zwitterionic polymers were successfully synthesized through sol–gel process. The polymer precursors were obtained by a reaction of N-[3-(trimethoxysilyl) propyl] ethylene diamine (TMSPEDA), under non-aqueous conditions, with 3-glycidoxypropyltrimethoxysilane (GPTMS), and followed by a reaction with γ-butyrolactone (γ-BL), and then exposure to open air to generate the hybrid zwitterionic polymers. The final polymers and products were characterized by FTIR, 13C NMR, TGA and conductometric titration curves. Both FTIR and 13C NMR spectra of polymers demonstrate the generation of ion pairs in these hybrid zwitterionic polymers. The TGA analysis reveals that the thermal stability of these types of hybrid zwitterionic polymers could go up to 350 °C. The relationships between conductivity and pH values show that the conductivities and the amphiphilic behaviors of hybrid zwitterionic polymers can be influenced by pH values; and the isoelectric point (IEP) of these kinds of hybrid zwitterionic polymers was pH 6.68–8.20, while the apparent contents of both anionic and cationic groups in the polymers are in the range of (1.1–2.1) × 10−4 and (2–8.0) × 10−5 mol/g, respectively. These kinds of polymers are expected to have applications to create anti-fouling membranes and single ionic conductors as well as to separate multi-valent ionic salts, etc.