Interactional behavior of surface active ionic liquid lauryl isoquinolinium bromide and anionic polyelectrolyte poly(4-styrenesulfonic acid-co-maleic acid) sodium salt in aqueous solution

Abstract

In the present study, we have reported a detailed assessment of interactional behavior between the surface active ionic liquid (SAIL) lauryl isoquinolinium bromide ([C12iQuin][Br]) and anionic polyelectrolyte poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSS-co-MA) in aqueous media. Various techniques such as surface tension, conductance, dynamic light scattering, and turbidity have been employed to get insight into interactions among [C12iQuin][Br] and polyelectrolyte in the interfacial region. Then, surface parameters such as surface excess concentration (Γcmc), surface pressure at interface (Πcmc), minimum area occupied by one molecule of SAIL at air–solvent interface (Αmin), adsorption efficiency (pC20), and surface tension at critical micelle concentration (cmc) (γcmc) have been calculated from tensiometric measurements. Further, thermodynamic parameters, i.e., standard enthalpy of micellization $$ \left(\Delta {H}_{\mathrm{m}}^{{}^{\circ}}\right) $$ , standard free energy of micellization ( $$ \Delta {G}_{\mathrm{m}}^{{}^{\circ}} $$ ), and standard entropy of micellization ( $$ \Delta {S}_{\mathrm{m}}^{{}^{\circ}} $$ ) have been evaluated. The size and shape of complexes formed among [C12iQuin][Br] and polyelectrolyte have been characterized using DLS and turbidity measurements.