Amphiphilic copolymers and surface active ionic liquid systems in aqueous media - Surface active and aggregation characteristics

作者：Singh D K; Sastry N V^*; Trivedi P A

来源：Colloids and Surfaces A: Physicochemical and Engineering Aspects , 2017, 524: 111-126.

DOI：10.1016/j.colsurfa.2017.04.033

• Surface active ionic liquids
• Block copolymers
• Mixed micelles
• Synergistic interactions
• Micellar dissolution

The surface active and micellar behavior of a di- and tri-block copolymer of EB and EBE, where E is oxyethylene and B is oxybutylene moieties and surface active ionic liquids (SAILs) namely 4-dodecyl-4-methylmorpholinium chloride, [C(12)mmor] [Cl] and 1-dodecyl-1-methylpyrrolidinium chloride, [C(12)mpyrr] [Cl]) is studied in aqueous media by surface tension, steady-state florescence and particle size measurements. The critical micelle concentration (CMC), surface active parameters (adsorption efficiency, surface excess, surface tension reduction, minimum area per molecule at air/water interface, etc.), average translation diffusion coefficient, size parameters and aggregation numbers are calculated. The effect of both SAILS and also copolymers as additives on the surface active and micellar behavior of one another is studied. The shape and size parameters of the micelles of the pure copolymer or SAILs are determined from translational diffusion coefficients at infinite dilution. The mixed micelles of copolymer SAIL systems are treated in terms of spheres and it is observed that their hydrodynamic radii decreased with the increase in the proportion of SAIL. The aggregation number of mixed micelles as determined from steady state florescence quenching method initially increased, reached a peak value and decreased drastically at high SAIL mole fractions. It is rationalized that the SAILs in general facilitate the dissolution of copolymer micelles but the mixed micelles predominantly consist of SAIL molecules or micelles over most of the mole fraction range. Regular solution theory formulations are tested on copolymer SAIL mixture solutions and micellar mole fraction, interaction parameter (0) and activity coefficients (f(1),f(2)) are calculated. The values of beta ranged from -3.3 to -5.9 suggesting synergistic interactions between the two amphiphiles.

• 出版日期2017-7-5