PREPARATION, PROPERTIES, AND APPLICATIONS OF VESICLE-FORMING CLEAVABLE SURFACTANTS WITH A 1,3-DIOXANE RING

A series of quaternary ammonium vesicle-forming surfactants was prepar ed by cyclization of 2,2-dialkyl-1,3-propanediols with 3-bromopropanal , followed by reaction with refluxing triethylamine. The critical vesi cle concentrations of these surfactants fell in the range of 10(-5)-10 (-6) M, which were smaller than the critical micelle concentrations of their counterparts containing only one alkyl chain. The fact that the destructibility of these surfactants was similar to their counterpart s bearing only one alkyl chain gave further evidence to the conclusion that the morphology, micelle or vesicle, has little effect on the hyd rolytic properties. The sonicated dispersions of these surfactants wer e single-compartment vesicles with their diameters ranging from 200 to 600 Angstrom. The reactions of TEMPO-12 with VC and TEMPO-OH with VC- 12 in the vesicle of 4b prepared by sonication or stirring were studie d by ESR spectroscopy with stopped-flow technique. The reaction behavi or was explained by the electrostatic attraction of VC/VC-12 by the ca tionic head groups of surfactants, the flip-flop motion and diffusion of the spin probe/VC-12, and the morphology of these vesicles. (C) 199 5 Academic Press, Inc.