Investigation of the Effects of Solvents and Temperature on the Aggregation, Binding, and Phase Partitioning Nature of Triton X‐100 with Promazine Hydrochloride

Abstract Herein, the aggregation, binding, and phase partitioning nature of triton X‐100 (TX‐100) with promazine hydrochloride (PMZ) have been examined applying spectroscopic and cloud point measurement methods. The PMZ mediated aggregation of TX‐100 was found to be disfavored with the elevation of temperature. The binding constant ( K b ) of the complexation of TX‐100 with PMZ was evaluated applying Benesi–Hildebrand (BH) plot, where the K b values showed the dependency on solvent composition and experimental temperature. Cloud point (CP) of TX‐100 + PMZ mixture was noticed to be reliant on both concentration and solvent variation. The micellization and complexation of the TX‐100 + PMZ system in all the investigated solvents were obtained as spontaneous with negative free energy changes( − Δ G m 0 / −Δ G b 0) $( { - \Delta G_{\mathrm{m}}^0/ -\!\! \Delta G_{\mathrm{b}}^{0\;}} )$ values, whereas clouding phenomenon was nonspontaneous ( + Δ G c 0 $ + \Delta G_{\mathrm{c}}^0$ ). For the TX‐100 + PMZ system, the enthalpy changes ( Δ H m 0 / Δ H b 0 / Δ H c 0 )$\Delta H_{\mathrm{m}}^0/\Delta H_{\mathrm{b}}^0/\Delta H_{\mathrm{c}}^0)\;$ and entropy changes( Δ S m 0 / Δ S b 0 / Δ S c 0 ) $( {\Delta S_{\mathrm{m}}^0/\Delta S_{\mathrm{b}}^0/\Delta S_{\mathrm{c}}^0} )$ values indicated the presence of hydrophobic interaction, dipole–dipole forces and π–π interactions. The compensation parameters (intrinsic enthalpy gain ( Δ H m 0 , ∗ / Δ H b 0 , ∗ / Δ H c 0 , ∗$\Delta H_{\mathrm{m}}^{0,*}/{{\Delta}}H_{\mathrm{b}}^{0,{\mathrm{*}}}/\Delta H_{\mathrm{c}}^{0,*}$ ) and compensation temperature ( T c )) were also calculated and explained logically.