An attempt to determine the polarity of bilayer of cationic and anionic surfactants vesicle: A chemical probe technique study

As core part of vesicle, the polarity of bilayer plays a key role on the stability and rigidness of the aggregate. In this paper, a novel chemical probe technique was successfully established to determine the polarity of the bilayer of the vesicle which was prepared from cationic and anionic surfactants with single chain, respectively. The thickness of bilayer of vesicle is only approximately 4 nm, therefore, the small size singlet oxygen with a long lifetime produced from dye-photosensitized oxidation has ability and sufficient time to diffuse out of the bilayer to react with the substrate incorporated in another vesicle's bilayer. The results show that the distribution ratio of the photooxidation products is related to the polarity of reaction medium and thus it can be used as a probe to determine the polarity of bilayer of the vesicle.