Synthesis and Self-aggregation Behavior of Novel Amphiphilic Polyelectrolytes Containing Gemini Surfactant Units

A novel class of amphiphilic polyelectrolytes bearing Gemini surfactant units were synthesized using the copolymerization of acryloyloxyethyltrimethylammonium chloride (D) and Gemini surfactant type monomer 1,3-bis(N,N-dimethyl-N-alkylammonium)-2-proplylacrylate dibromide(G) (alkyl = tetradecyl or cetyl). The self-aggregation properties of these polyelectrolytes in aqueous solution were investigated by steady fluorescence, conductivity, dynamic light scattering (DLS) and Transmission electron microscopy(TEM) techniques as the function of the molar fraction of Gemini surfactant units in the polyelectrolyte. It was found that the critical aggregation concentration(CAC) decreases with the increase of molar fraction of Gemini surfactant segments and the length of alkyl chain on the gemini surfactant units. Two kinds of aggregates coexist in the solution, one of which is suggested to be intrapolymer aggregate and the other is interpolymer aggregate. With the increase of alkyl chain length, the polyelectrolytes exhibit a strong preference for intrapolymer hydrophobe self-aggregation. With the increase of molar fraction of Gemini segments, the hydrodynamic radius (R-b) increases in the case of D14G and oppositely decreases slightly in the case of D16G.