Structural Characterization of Nonionic Surfactant Reverse Micelles in Diglycerol Monolaurate/Squalene System

摘要

Structure of nonionic surfactant diglycerol monolaurate (C_(12)G_2) reverse micelles in squalene at different surfactant concentrations and temperatures is presented. For the structural characterization of the micelles, small-angle X-ray scattering (SAXS) technique is used. The scattering data is evaluated by virtually model free generalized indirect Fourier transformation (GIFT) method. GIFT analysis of the SAXS data has shown the clear evidence on the formation of rod-like micelles in the C_(12)G_2/squalene system at higher temperatures. At fixed temperature, increasing surfactant concentration induces one-dimensional micellar growth; the maximum length of the micelles increases with concentration, but the micellar cross-section remains essentially the same. On the other hand, at fixed concentration, the maximum length of the micelles decreases with the rise of temperature. It is found that the length of micelles decreases by ～35% keeping cross-section diameter unchanged with the rise of temperature from 60 to 80°C in 5 wt% C_(12)G_2/squalene system.