Interaction of (Hydroxypropylmethyl)cellulose with Anionic Surfactants

Abstract

Abstract The aggregation process between (hydroxypropylmethyl)cellulose (HPMC 0.20% m/m) and three anionic surfactants namely sodium cholate (CS), sodium deoxycholate (DC) and sodium dodecylsulphate (SDS), in aqueous dilute solutions, was investigated by fluorescence, electrical conductivity, dynamic light scattering (DLS) and small angle X‐ray scattering (SAXS) techniques. Through fluorescence, the critical micelle concentration (CMC) and critical aggregation concentration (CAC) of the systems were obtained in good agreement with those obtained from conductivity. Also by means of conductivity measurements, once the experiments were undertaken at four temperatures, the thermodynamic parameters of the micellization process were calculated. From DLS, the relaxation time distribution functions were analyzed by REPES Routine, revealing that the surfactants bind to the polymer before CAC as well as the formation of free micelles at high surfactant content. The SAXS technique confirmed the existence of such free micelles.