Abstract
Herein, in the presence of electrolytes, the cloud points (CPs) of the mixture of a conventional uncharged amphiphile (triton X-100 (TX-100)) and promethazine hydrochloride (PMH; phenothiazine medicine) were measured and explained in great details. The CP values of the employed surfactant + PMH system were reduced with enhancing salts contents (NaCl, Na2SO4, NH4Cl, and (NH4)2SO4)), while the CP values of the study system followed the trend: Na2SO4 < NaCl and (NH4)2SO4 < NH4Cl. The different thermodynamic parameters of phase separation, including standard free energy (ΔG0c), enthalpy (ΔH0c), and entropy (ΔS0c) changes were also calculated and discussed elaborately. The values of free energy change (ΔG0c) were obtained to be positive, indicating that the clouding phenomena are non-spontaneous. Different transfer properties (free energy (ΔG0c.t), enthalpy (ΔH0c,t), and entropy (ΔS0c,t) of transfer), intrinsic enthalpy gain (ΔH0,*c) and compensation temperature (Tc) of the inspected system have also been assessed and discussed.