On Negative Birefringence in Water‐in‐Oil Microemulsions

Abstract

Abstract The occurrence of a negative birefringence in water‐in‐oil (W/O) microemulsions has been substantiated and analyzed. The analysis is based on the well‐established aqueous nanodroplet model of W/O microemulsions. In the particularly investigated water/sodium bis(2‐ethylhexyl)sulfosuccinate (AOT)/aliphatic oil systems, the AOT monolayer exhibits a negative induced intrinsic birefringence, which is brought about by the pronounced polarizability of the alkyl moiety of the AOT molecule approximately perpendicular to the direction of its permanent dipolement.