Highly stable polymerizable vesicles in anionic surfactant/ammonium salt mixtures in the presence of cross-linking monomers for convenient preparation of hollow nanospheres.

Spontaneous and stable vesicles are formed from vinylbenzyltrimethylammonium chloride (VBTAC) and sodium dodecyl sulfate (SDS) ranging in molar composition from 3:7 to 7:3 in the presence of 30 mol % divinylbenzene (DVB). Dynamic light scattering analysis and transmission electron microscope observations revealed that microparticles with diameters around 120 nm (30%) and 580 nm (70%) were formed. Trapping efficiency of the vesicles examined with D-(+)-glucose amounted to ca. 15%. These vesicles were capable of undergoing polymerization in the presence of water-soluble radical initiators such as 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride to fix the vesicular structure. Retention of the vesicle size and bimodal size distribution characteristics during the polymerization indicated that intravesicular polymerization prevailed over the intervesicular process. SDS was stably retained in the cross-linked vesicle and was not removed from the vesicle by exhaustive dialysis or ultrafiltration, due to the electrostatic interaction within the cross-linked polymeric framework produced from VBTAC and DVB. The resulting hollow nanospheres are readily redispersed in water without the aid of additional surfactants.