||A physical gel is a substantially dilute network in which junctions can break and recombine due to thermal fluctuation, i.e., the junctions have the finite lifetime. When in the steady-state, it exhibits no flow. In general, reversible gels are formed by polymers, with weak attractions like hydrogen bonds, for example, biopolymers gelatin and agar.|
Typically, the surfactant gel is referred to the cationic surfactant/water system involving cetyl-trimethylammonium bromide (CTAB). However, it is generally believed that CTAB surfactant molecules assemble into worm-like micelles in aqueous media and yield a transient network structure due to the topological entanglement of the micelles. As a result, it is more like a viscoelastic solution rather than a jelly-like gel.
In this work, the gelation of a surfactant solution involving anionic surfactant/water system including sodium laurate (NaL) and sodium tetradecanoate (NaM) is explored by rheological properties measurement and differential scanning calorimetry. The surfactant solution transforms from a transparent liquid to a white opaque gel upon lowering the temperature and vice versa. The characteristics of the surfactant gel is confirmed by the fact that the storage module G”is greater than the loss module G”. In addition to investigate the gelling mechanism such as the nature of associative bonds and microscopic structure, the effects of surfactant concentration, alkyl chain length, and salt addition on the gel properties are studied as well.
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