Charge-free reverse wormlike micelles in nonaqueous media.

ABSTRACT

We report a facile method for the formation of charge-free reverse wormlike micelles in a nonionic surfactant/oil system without addition of water under ambient conditions. This route involves the addition of sucrose dioleate (SDO) to semidilute solutions of sucrose trioleate (STO) in hexadecane. A reverse wormlike micelle was possible to achieve only with ionic surfactants in which water and/or salts are fundamentally required to induce micellar growth so far. In this contribution, we have shown that less lipophilic nonionic surfactant SDO promotes one-dimensional growth to STO reverse micelles and leads to the formation of transient networks of viscoelastic reverse wormlike micelles. The zero-shear viscosity increases by ∼4 orders of magnitude, and it is the mixing fraction of SDO to STO that determines the viscosity growth. The structure and dynamics of the reverse micelles are confirmed by small-angle X-ray scattering (SAXS) and rheometry measurements.