Change in the two-step flow behavior on aging the ternary mixture comprising monoalkyl cationic surfactant, long-chain alcohol and water II. Analysis of the creep behavior

Abstract

A two-step development of the internal structure on aging the ternary mixture comprising cetyltrimethylammonium chloride (C 16CA), cetyl alcohol (C 16OH), and water was elucidated from the change in the creep behavior. The system was expressed by a six-element model comprising two Voigt units in series with a Maxwell unit. A similar increase in the instantaneous elastic modulus G 0, the Newtonian viscosity η 0, and the elastic modulus and viscosity of the Voigt units ( G 1, η 1) with a longer retardation time τ 1 were observed on aging up to 1–3 days, followed by a leveling off. Conversely, the elastic modulus and viscosity of the Voigt units ( G 2, η 2) with a shorter retardation time τ 2 were constant at the beginning, followed by an increase on aging. From a cryo-SEM observation, we confirm that the two-step development considered from the creep properties on aging was caused by an initial coagulation to form a network of multilamellar vesicles, and a subsequent phase transition from vesicles to lamelae.