Ummer Farooq

Effect of the nature of counterion on the micellar properties of cationic surfactants: a conductometric study

ABSTRACT Interaction of cationic surfactants, tetradecyltrimethylammium bromide (TTAB) and tetradecyltrimethylammonium chloride (TTAC) with anionic dye, tartrazine in aqueous solution has been investigated employing conductometric technique. The free energy of transfer of hydrophobic chain, , surface contribution, and their transfer values, and , free energy, , enthalpy, , and entropy, of micellisation have been calculated. A marked decrease in the critical micelle concentration for TTAB compared to TTAC indicates dramatic role of the smaller counterion Br− over the bigger counterion Cl−. Formation of dye–surfactant ion-pairs which behave as nonionic surfactant has been proposed. Higher negative and positive values for TTAB than TTAC are attributed to difference in the size and nature of the counterions Br− and Cl−. Negative and values clearly suggest that micellisation of TTAB and TTAC is thermodynamically spontaneous and exothermic in nature. As ), it suggests that the process of micellisation is entropy dominated for the two surfactants.

Study of Intermolecular Interactions of CTAB with Amino Acids at Different Temperatures: A Multi Technique Approach

Abstract The densities, ρ, viscosities, η and specific conductivities κ, of (0.0002, 0.0004, 0.0006 and 0.0008 m) CTAB in 0.1 m aqueous valine, leucine and isoleucine were measured at different temperatures. The measured data were used to calculate various useful thermodynamic parameters. A complete characterization of any mixture can be performed by means of these thermodynamic properties. The apparent molar volume, ϕv, partial molar volume, ϕv0

Interaction of a Surface-Active Ionic Liquid with an Antidepressant Drug: Micellization and Spectroscopic Studies

\phi _v^0

Interactions of Cationic, Anionic and Nonionic Surfactants with Cresol Red Dye in Aqueous Solutions: Conductometric, Tensiometric, and Spectroscopic Studies

and partial molar isobaric expansibilities, ϕE0,

Interaction of Cetrimide with Nonionic Surfactants—Triton X-100 and Brij-35: A Conductometric and Tensiometric Study

\phi _E^0,

Self-aggregation of ionic liquid-cationic surfactant mixed micelles in water and in diethylene glycol–water mixtures: Conductometric, tensiometric, and spectroscopic studies

were calculated using density data. The viscosity data were analyzed using Jones–Dole equation to obtain viscosity coefficients, A- and B-, free energy of activation per mole of solvent, Δμ1°∗, and solute, Δμ2°∗, enthalpy, ΔH∗ and entropy, ΔS∗ of activation of viscous flow. Measuring the changes in these properties has been found to be an excellent qualitative and quantitative way to obtain information regarding the molecular structure and intermolecular interactions occurring in these mixtures. Various structure-making/breaking ability of solute (cetyltrimethylammonium bromide) in presence of aqueous amino acid solutions were discussed. In addition, fluorescence study using pyrene as a photophysical probe has been carried out, the results of which support the conclusions obtained from other techniques.

Interaction of hexadecylpyridinium bromide with glycine in aqueous medium using the Krafft temperature from conductivity measurement

The interaction of the antidepressant drug nortriptyline hydrochloride (NOT) with the surface-active ionic liquid (SAIL), 1-decyl-3-methylimidazolium chloride, [C10mim][Cl], has been studied using multiple techniques, including conductometric titration, tensiometric, fluorometric, dynamic light scattering and UV–visible spectrophotometric measurements. There is a significant decrease in the cmc of SAIL on the addition of the drug NOT, indicating adsorption of drug molecules in the outer portion of the micelle. In the present study, the values of the packing parameter, P, lie in the range of 0–0.3, which suggests that the micelles formed are spherical in nature. More negative values of the standard Gibbs energy of adsorption,

Effect of tartrazine dye on micellisation of cationic surfactants: conductometric, spectrophotometric, and tensiometric studies

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