SYNTHESIS AND INTERFACIAL PROPERTIES OF POLYMERIZABLE AND NONPOLYMERIZABLE SURFACTANTS HAVING AN ACTIVE ESTER GROUP

Novel polymerizable and nonpolymerizable surfactants bearing an active ester group, p-10-undecenoyloxyphenyldimethylsulfonium methylsulfate (UPDS) and p-lauroyloxyphenyldimethylsulfonium methylsulfate (LAPDS), were synthesized. Their aqueous solutions were characterized in terms of the critical micelle concentration (CMC), the micellar aggregation number (N-s) at a concentration slightly above the CMC, and the area p er molecule at surface saturation for adsorption at the water-air inte rface (a(m)) at 25 degrees C, mainly to evaluate the hydrophilicity of dimethylsulfonium methylsulfate as the head group. The CMC, N-s, and a(m) values were, respectively, (3.0-6.5) X 10(-3) M, 42, and 105 Angs trom(2) for UPDS and (1.5-2.2) X 10(-3) M, 88, and 60 Angstrom(2) for LAPDS. These values for LAPDS were in good agreement with those for n- alkyltrimethylammonium bromide with an alkyl chain length correspondin g to 15.5 carbon atoms. Based on the results and the hydrophobicity of the tail group, it was concluded that the dimethylsulfonium methylsul fate group has a hydrophilicity comparable to that of a trimethylammon ium bromide group. The terminal double bond in the tail group of UPDS was also found to disturb a molecular orientation in both the micelliz ation and the adsorption at the water-air interface. UPDS and LAPDS we re readily reacted with 2-methoxyethylamine in water at room temperatu re to give their corresponding amides in high yields, being indicative of the high reactivity of their ester group. (C) 1995 Academic Press, Inc.