Abstract
•Mixed micelle study of TTAB & CTAB mixture in presence of drug.•Achieved CMC of pure/mixture of surfactants were dependent on drug concentration.•ΔHm0 and ΔSm0 values reveal that micellization is driven jointly by both enthalpy and entropy.•Counterion dissociation (g), micellar composition, compensation temperature, etc. were also reported.•Values of intrinsic enthalpy also reveal the stability of formed micelles.
The formation of mixed micelle of tetradecyltrimethylammonium bromide (TTAB) & cetyltrimethylammonium bromide (CTAB) mixture has been carried out in appearance of ceftriaxone sodium trihydrate (CTS) drug having different concentrations over a temperature range of 298.15 to 323.15 K, keeping a break of 5 K. The CMC of pure and mixture of surfactants were observed to be reliant on the concentration of drug. The CMC values of TTAB + CTAB mixture lie in between that of pure TTAB & CTAB. The larger deviation of CMC of TTAB & CTAB mixture from the corresponding ideal CMC (CMCid) at higher mole fraction (α1) of CTAB signify stronger interaction amid TTAB and CTAB at higher bulk α1 of CTAB. The negative excess free energy (ΔGexRub) values reveal the stable form of micelle and the stability was attained to be enhanced by the rise of α1 of CTAB. The interaction parameter (β) also reveals the attractive interaction amongst the studied species of surfactants. The micellar mole fraction (X1Rub), as well as its ideal (X1id) values, experience an augmentation by the rise of α1, which reveal that the contribution of CTAB increase with the raise of α1. The Gibbs free energy of micellization (ΔGm0) reveals a spontaneous association of both pure and mixed systems. The enthalpy (ΔHm0) and entropy (ΔSm0) of micellization reveal that the micellization is exothermic in nature, while the recommended forces are hydrophobic interaction, along with weak electrostatic interactions. The values of intrinsic enthalpy also reveal the micelle’s stability, thereby, formed. Degree of dissociation (g), compensation temperature, etc., were also reported.