CRYO-TRANSMISSION ELECTRON-MICROSCOPY STUDY OF VESICLES AND MICELLES IN SILOXANE SURFACTANT AQUEOUS-SOLUTIONS

A vesicle-micelle transition and intermediate structures in ABA and ra ke-type siloxane surfactants are reported. At low surfactant concentra tions, systems show vesicles of various sizes coexisting with spheroid al micelles and elongated micelles about 80 angstrom in diameter. In s ome instances wormlike micelles are seen in the system with vesicles. Intermediate structures such as open vesicles and pieces of lamellae a re also observed. These suggest that when the vesicle-to-micelle trans ition takes place, the vesicle first opens and then breaks into fragme nts of lamellae, which finally transform into either spheroidal or wor mlike micelles. Toroidal vesicles are also reported.