Effect of composition of mono/di-hydroxy organic compounds and temperature on the aggregation behavior and physico-chemical properties of polyvinyl alcohol + TTAB mixture

Abstract

Herein, the aggregation manners of polyvinyl alcohol (PVA) with tetradecyltrimethylammonium bromide (TTAB) in alcohols/diols media containing various concentrations and at several temperatures were performed using the conductivity measurement technique. Different physico-chemical parameters, such as critical micelle concentration (CMC), fraction of bound counter ions (β) and thermodynamic properties (ΔGo m, ΔHo m, ΔSo m, and ΔCo m) for the TTAB + PVA mixture in aqueous solutions of EtOH (EtOH), 1-propanol (1-PrOH), ethylene glycol (EG), and propylene glycol (PrG), have been determined. The CMC values were found to undergo a decrease in 1-PrOH in comparison to the values obtained in aqueous media, but in EtOH, the CMC value firstly decreases, touches the lowest point, and then exhibits an upsurge with further increase of the percentage of EtOH. The observed greater CMC values in diols media disclose that the micelle formation of TTAB + PVA mixture is delayed in the manifestation of diols. The CMC values of TTAB + PVA mixture have also been observed to vary with the change of study temperature. The negative values of ΔG0 m were obtained for all circumstances suggesting a spontaneous aggregation phenomenon of TTAB + PVA system. The values of ΔH 0 m and ΔS0 m dictate that the PVA molecule interacts exclusively with TTAB through the formation of hydrogen bonding, ion-dipole, and hydrophobic interaction. Furthermore, the standard molar heat capacity (ΔC 0 m), compensation temperature (T c), intrinsic enthalpy gain (ΔH 0,* m), and the thermodynamic properties of transfer (ΔG 0 m.tr, ΔH 0 m.tr. and ΔS 0 m.tr.) for the studied system were assessed and demonstrated with appropriate explanations.