Polymers containing quaternary ammonium groups based on poly(N-vinylimidazole)

A poly(N-vinylimidazole) (PNVI)—based poly(carboxybetaine) with two methylene groups between the opposite charges was achieved by the nucleophilic addition reaction of the mentioned aminic polymer to the carbon–carbon double bond of acrylic acid (AA). Treatment of poly(carboxybetaine) with concentrated HCl (2 N) for long time leads to the corresponding cationic polyelectrolyte. The poly(carboxybetaine) is soluble in both water and aqueous solutions of salts such as: LiCl, NaCl, NaHCO3, CaCl2, Na2SO4. In water and in the first three salts, poly(carboxybetaine) exhibits a non-polyelectrolyte behaviour (a linear dependence of reduced viscosities on polymer or salt concentration), while in the remaining two salts, a slight polyelectrolyte behaviour is observed. The cationic polyelectrolyte is soluble in water and aqueous solutions of LiCl, NaCl, CaCl2 and NaHCO3, except Na2SO4. It has a polyelectrolyte behaviour in all solutions. Also, the binding trends of the added salts by polymers are discussed.