Physicochemical Studies on the Interfacial and Micellization Behavior of CTAB in Aqueous Polyethylene Glycol Media

Abstract

Interfacial and micellization behavior of cetyltrimethylammonium bromide (CTAB) have been studied in aqueous polyethylene glycol (PEG) mixed solvent systems of varying concentrations and molar mass. Interfacial behavior of CTAB was investigated by the equilibrium surface tension method. Conductance studies of surfactant solutions under different condition helped in determining the critical micelle concentration (CMC) and degree of dissociation of CTAB micelles. In addition, the limiting molar conductivity of surfactant and micellar species were evaluated from the differential plots. The CMC of CTAB was found to increase with increasing PEG concentration as well as its molar mass, although, the process of interfacial adsorption and micellization was found to be spontaneous, as evidenced by negative free energy change. The viscosity of CTAB micelles in aqueous-PEG mixtures was found to increase with the increase in PEG concentration and molar mass. Dynamic light scattering measurements revealed a size enhancement effect contributed by the PEG oligomers. An increase in the CMC of CTAB and the subsequent presence of a higher number of ionic species in their dissociated form was further established by an overall increase in the zeta potential value in the presence of PEG oligomers. It is proposed that the PEG could wrap around the micelles through their conformational changes. Results also suggest that PEG oligomers could give solvophobic effect which enhances the CMC of CTAB compared to that in pure water.

Magnetically Modulated Pot‐Like MnFe2O4 Micromotors: Nanoparticle Assembly Fabrication and their Capability for Direct Oil Removal

“…Here, r and v are 12.5 μm and 200 μm s −1 , referring the radius and speed of the autonomous moving micromotor in Figure . η is the dynamic viscosity of the aqueous medium (1.23 × 10 −3 Pa s) . The magnetic force on the magnetic micromotor can be considered as the sum of the individual forces on each single‐domain or single superparamagnetic MnFe 2 O 4 NP.…”

Effect of Head Groups, Temperature, and Polymer Concentration on Surfactant—Polymer Interactions

“…do not interact with polymers having low molecular weight. Although there are some reports on surfactantpolymer interactions in recent years [13][14][15], the comparison of surfactants having different charge and head group in the presence of a single polymer possessing high molecular weight at different temperatures has not been done earlier. Therefore, in the present work the micellization behaviour of surfactants having different head groups [sodium dodecyl sulphate (SDS), sodium dodecylbenzenesulfonate (SDBS), cetylpyridinium chloride (CPC), hexadecyltrimethylammonium bromide (HTAB), and tetradecyltrimethylammonium bromide (TTAB)] in water and in aqueous solutions of PEO (molecular weight = 100,000) in the concentration range [0.005-0.04 %(w/v)] over the temperature range (288.15-318.15 K) has been studied using conductivity, surface tension, and viscosity methods.…”

Physico-Chemical Studies on the Interaction of Bacterial Polysaccharide- Surfactant Aggregates with Special Reference to their Hydrodynamic Behavior

“…Viscosity was measured at different shear rates for different SPS-surfactant concentrations. Zero shear viscosity was determined from the intercept of the plot of apparent viscosity vs. shear rate 44,45 . Temperature was controlled at 298 K using a thermostatic water bath with an accuracy of 0.1 K.…”