Surface, compressibility and viscometric measurements of binary system containing cationic surfactant with achiral amino acid at different temperatures

Abstract

In the preset manuscript, we intend to examine the type of solute-solvent interactions present in such system which is valuable to food/pharmaceutical sector. A systematic knowledge of the volumetric properties in conjunction with other thermodynamic properties provides useful information about water-solute interactions. We examine, therefore, surface tension, density, speed of sound and viscosity for binary system contains cationic surfactant cetyltrimetylammonium bromide (CTAB) in aqueous glycine solution (0.2, 0.3 and 0.4) mol/kg at four different temperatures ranging from (298.15 to 313.15) K. The surface tension result indicates the change in critical micelle concentration (CMC) values in the presence of additive. Various thermodynamic and adsorption parameters like surface excess, Γmax, minimum area at air-liquid interface, Amin etc. have been evaluated form surface tension data. The density and speed of sound measurements have been used to calculate the apparent molar volume and adiabatic compression which reveals the kind of interactions present pertaining to hydrophilic-hydrophillic and ion-hydrophillic interactions. In addition, hydrophobic hydration also plays a key role especially at higher surfactant concentration. Viscosity data further strengthen the concept of hydrophobic interactions present in the binary solution taken into consideration the relative viscosity and viscous relaxation time parameters. The effect of temperature and additive for all the calculated parameters has also been discussed in detail.