Effect of percentage of methanol on micellization position of mixed surfactant interaction in the absence and presence of dye

Abstract

The interaction behavior of mixed surfactant-dye systems, i.e., anionic surfactant sodium dodecyl sulfate (SDS), cationic surfactant cetyl pyridinium chloride (CPC), and dye methyl orange (MO) was investigated through the allocation of micelles using conductivity measurements. Conductivity as a function of surfactant concentration was monitored to calculate the critical micelle concentration (CMC). The conductivity increased sharply as the surfactant content increased, according to the results. Moreover, the conductivity rises with temperature, whereas it falls with increased methanol (CH₃OH). CH₃OH-H₂O mixed solvent media containing 0 %, 10 %, 20 %, and 30 % of CH₃OH at 298.15, 308.15, and 318.15 K to work out the basic micelle fixation, gives significant understanding to the arrangement of the mixed surfactants. The CMC and degree of micellar dissociation (α) of SDS with CPC increase in the CH₃OH and H₂O mixture. The CMC and α values are increased by increasing the temperature. Various thermodynamic parameters, i.e. Standard free energy of micellization (${\Delta G}_m^o$), Standard enthalpy of micellization (${\Delta H}_m^o$), and Standard entropy of micellization (${\Delta S}_m^o$) were computed in SDS-CPC without MO. ${\Delta G}_m^o$ values for SDS-CPC in the presence of MO results in micellization more probable with MO.