The influence of organic and inorganic additives on the polymer mediated phase separation of Triton X-100

Abstract

Herein, the investigation of the phase partition mode of the mixture of Triton X-100 (TX-100) + sodium carboxymethyl cellulose (SCMC) was performed in presence of different organic and inorganic additives media. Results reveal that the phase separation behavior of TX-100 is facilitated by the presence of SCMC. The cloud point (CP) of the TX-100 + SCMC mixture was observed to be enhanced in presence of alcohols (ethanol (EtOH) and 1-propanol (1-PrOH)) as well as diols (ethanediol (ED) and propanediol (PD)), with more prominent results seen in the case of PD. The presence of salts causes earlier phase separation. The values of Gibbs free energy (ΔGco) were positive but decreased as the concentration of the additives (both organic and inorganic) increased. This revealed that the phase separation of the TX-100 + SCMC mixture was thermodynamically non-spontaneous, and the extent of its non-spontaneity decreased as the concentrations of both organic and inorganic additives increased. The phase segregation is enthalpy-controlled in an aqueous medium, while it is entropy-controlled in aqua-organic media, although it demonstrates the opposite result at greater concentrations of organic additives. The magnitudes of enthalpy (ΔHco) and entropy (ΔSco) of clouding were found to be negative and positive at lower and upper concentration of electrolytes, respectively. The magnitudes of ΔHco and ΔSco reveal that the hydrogen bonding, hydrophobic interaction, dipole-dipole and ion-dipole interactions are the key forces of interaction between TX-100 and SCMC. Different transfer energies and enthalpy-entropy compensation are also discussed.