Synthesis and aqueous solution characterization of novel diblock polyampholytes containing imidazole

A series of diblock copolymers of 2-(1-imidazolyl)ethyl methacrylate and tetrahydropyranyl methacrylate (THPMA) were synthesized by group transfer polymerization using propylene carbonate rather than tetrahydrofuran as the solvent to ensure homogeneous polymerizations. The resulting copolymers were characterized by gel permeation chromatography and proton nuclear magnetic resonance spectroscopy (1H NMR) to determine their molecular weights and compositions, respectively. The THPMA units of the copolymers were subsequently converted to methacrylic acid units by acid hydrolysis. The resulting polyampholytes were characterized in terms of their composition and solubility characteristics using 1H NMR and hydrogen ion titration. Moreover, dynamic light scattering in alkaline water (pH 9.3) indicated the presence of large non-micellar aggregates of the block polyampholytes.