Inquisition of micellar and surface active properties of gemini surfactants in the presence of a dipeptide

Abstract

Abstract The influence of dipeptide glycyl-l-valine (gly-l-val) on the micellization and surface active properties of two different gemini surfactants varying in their spacer group i.e. ethylene-1,2-bis (N,N-dimethyl-N-dodecylammonium bromide) (12–2–12) and hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) (12–6–12) was explored using tensiometry as well as conductivity technique. Conductivity measurements at several temperatures (293.15, 298.15, 303.15 and 308.15) K and tensiometric measurements at 298.15 K at several concentrations of dipeptide (0.02, 0.04 and 0.06) mol/kg were conducted so as to deduce the interactions amid dipeptide and two surfactants. Several parameters viz. critical micelle concentration (CMC) as well as the degree of ionization (α) along with various parameters associated with thermodynamics; standard entropy of micellization ( Δ S m 0 ${\Delta}{S}_{m}^{0}$ ), Gibbs free energy of micellization ( Δ G m 0 ${\Delta}{G}_{m}^{0}$ ) and standard enthalpy of micellization ( Δ H m 0 ${\Delta}{H}_{m}^{0}$ ) have been evaluated through conductivity data. Various additional thermodynamic parameters such as free energy of adsorption ( Δ G a d 0 ${\Delta}{G}_{ad}^{0}$ ) and surface free energy ( G min s ${\left(G\right.}_{\mathrm{min}}^{s}$ ) have been also estimated through surface tension measurements.