Synthesis of water-soluble oligomers from imidazole, ethyleneglycol diglycidyl ether, and methacrylic acid: an insight into the chemical structure, aggregation behavior and formation of hollow spheres

Abstract

The synthesis of non-soluble polyampholytes was modified to obtain water-soluble oligomers, by a sequential reaction at 60 °C of imidazole (IM), ethyleneglycol diglycidyl ether (EGDE) and methacrylic acid (MAA). The hydrogel Poly(EGDE-IM) with disubstituted imidazole (IM+) residues, enhanced its solubility in water by functionalization with Poly(MAA). NMR and mass spectrometry evidenced ester groups, Poly(MAA) chains, Poly(EGDE), and IM+ links. Capillary electrophoresis evidenced populations with positive net charge at pH lower than 9, due to IM+ and protonatable residues (IMH+). Water-soluble aggregates of oligomers were detected by size exclusion chromatography. The product aggregated with cations such as Fe(II) adsorbing anionic compounds, and formed hollow spheres when citric acid was present.