RESEARCH ARTICLE Impact of different diols/polyols on the phase separation behavior as well as thermodynamic properties of tween 80 Afroja Akter Mishu 1 | Md. Ruhul Amin 1 | Malik Abdul Rub 2,3 | Md. Anamul Hoque 1 | Shariff E. Kabir 1 | Abdullah M. Asiri 2,3 1 Department of Chemistry, Jahangirnagar University, Dhaka, Bangladesh 2 Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia 3 Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia Correspondence Dr Malik Abdul Rub, Assistant Professor, Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia. Email: malikrub@gmail.com Abstract Herein, the cloud points (CPs) of tween 80 (Tw 80) in water/(water + diols [ethanediol, propanediol, and butanediol])/(water + polyols [glucose, fructose, and sorbitol]) systems were measured. For diols‐Tw 80‐water system and polyols‐Tw 80‐water system, the CP values were obtained to reduce gradually with increasing content of diols and polyols at a particular concentration of Tw 80. For a certain concentration of Tw 80 having different contents of diols, the observed ΔH 0 c , as well as ΔS 0 c values, were negative over the range of con- centration of diols studied, and the negative values of ΔH 0 c and ΔS 0 c were reduced with the enhancement of the content of diols. The values of ΔH 0 c were negative, which indicate the process was exothermic. The clouding process of Tw 80 in the presence of different diols is mainly enthalpy‐controlled process, while the contributions of enthalpy tend to reduce with enhancing of the con- tribution of diols. In the case of polyols‐Tw 80 mixture in an aqueous environ- ment, the ΔG c 0 values were achieved positive. The values of ΔH c 0 and ΔS c o were obtained negative for studied systems, while the negative values reduce with enhancing of polyol (glucose and fructose) concentrations. For sorbitol‐ Tw 80 system, the values of ΔH c 0 were observed to be negative and the nega- tive magnitudes reduce with enhancing of sorbitol concentrations. The thermo- dynamic parameters of transfer are also evaluated and illustrated in detail. KEYWORDS alcohols, cloud point, polyols, thermodynamic parameters, Tw 80 1 | INTRODUCTION The solution properties of nonionic surface active agent are notably different from that of ionic surfactants. A dis- tinct property for nonionic surfactant solution is acute phase separation under the application of heat to the solution. This phase separation occurs at a definite tem- perature and this is called a cloud point (CP). [1] Micelles formation is one of the most significant properties of sur- factant. [2–5] The numerical value of CP for nonionic surfactants are notably sensitive to the attendance of any additive. Additions of any element/compounds (organic solute, dye, drug, electrolyte, salts, etc) in the system, even at very low concentration make the change of CP values. As the additives specifically change the CP of nonionic surfactant, so this is a tool to use the item as per the requirement of various condition and purposes by a convenient increase or decrease of a number of addi- tives. The CP values of nonionic surfactant are useful and characteristic property of nonionic surfactant compared Received: 20 April 2019 Revised: 14 June 2019 Accepted: 28 June 2019 DOI: 10.1002/poc.4001 J Phys Org Chem. 2019;e4001. https://doi.org/10.1002/poc.4001 © 2019 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/poc 1 of 10