RESEARCH ARTICLE Investigation of mixed micellization study of sodium dodecyl sulfate and tetradecyltrimethylammonium bromide mixtures at different compositions: Effect of electrolytes and temperatures Md. Zahid Hasan 1 | Shamim Mahbub 1 | Md. Anamul Hoque 1 | Malik Abdul Rub 2 | Dileep Kumar 3,4 1 Department of Chemistry, Jahangirnagar University, Dhaka, Bangladesh 2 Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia 3 Division of Computational Physics, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam 4 Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam Correspondence Dileep Kumar, Division of Computational Physics, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam. Email: dileepkumar@tdtu.edu.vn Funding information Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah, Grant/ Award Number: DF-768-130-1441 Abstract Herein, we employed the conductometric measurement technique for the esti- mation of the interaction between two oppositely charged surfactants (anionic, sodium dodecyl sulfate [SDS] and tetradecyltrimethylammonium bromide [TTAB]) in two chloride (NaCl/NH 4 Cl) salts in the range of temperatures from 298.15 to 318.15 K. The deviation of experimental critical micelle concentra- tion (cmc) from the corresponding ideal values of cmc (cmc id ), the values of interaction parameters (β), and activity coefficients (f 1 and f 2 ) of the compo- nents reveal the existence of the interaction amongst the investigated compo- nents. The attained cmc values for SDS/SDS + TTAB decline with the rise of temperature in H 2 O/electrolytes medium. The reduction of cmc in the pres- ence of electrolytes reveals the facilitated micellization in the electrolyte medium. The assessed values of the micellar mole fraction of TTAB (X 1 ) obtained from theoretical models signify the significant contribution of TTAB in SDS + TTAB mixed micellization. The estimated negative values of free energy (ΔG o m ) and excess free energy (ΔG ex ) of micellization reveal that micellization is spontaneous and mixed micelles are extra stable than distinct micelle, respectively. The enthalpy (ΔH o m ) and entropy (ΔS o m ) in addition trans- fer energies of micellization were also evaluated and explained thoroughly. KEYWORDS interaction parameter, mixed micelle, SDS, thermodynamics, TTAB 1 | INTRODUCTION The organic compounds having both polar and apolar parts in the structure of the same molecule are known as surfactants that show unique solubility property as well as aggregation behavior in aqueous medium. [1] This aggregated form of surfactant (micelle) occurred due to the balance of hydrophilic and hydrophobic interaction beyond their particular concentration which is termed as critical micelle concentration (cmc) and any concentra- tion inferior to cmc, surfactant exists in monomeric form. [2,3] The extent of interaction of the surfactant mole- cules is a function of the microenvironment. Thus, any change of microenvironment of a surfactant for example presence of additives, addition of second surfactant, and temperature is the cause of modified hydrophilic and Received: 26 September 2019 Revised: 24 November 2019 Accepted: 20 December 2019 DOI: 10.1002/poc.4047 J Phys Org Chem. 2020;e4047. wileyonlinelibrary.com/journal/poc © 2020 John Wiley & Sons, Ltd. 1 of 17 https://doi.org/10.1002/poc.4047