Ion‐Specific Effects on Clouding and Micellization Thermodynamics of X‐Shaped Tetronic Block Copolymers
Dipali Roy, Bappaditya Naskar, Tanushree BalaABSTRACT
Investigation of the thermodynamics of polyethylene oxide (PEO) and polypropylene oxide (PPO) containing block copolymer solution in the presence of various types of ions is essential for understanding their physicochemical properties and industrial applications. In this study, we report salt‐dependent clouding and micellization behaviors of two block copolymers, T701 and T90R4, along with the associated thermodynamics. The critical micellar concentration (CMC) and cloud point (CP) are found to decrease following the order NaSCN> NaI> NaNO 3 > NaBr> NaCl> Na 2 WO 4 > Na 2 MoO 4 > Na 2 SO 4 > Na 3 PO 4 , which is consistent with the Hofmeister series from chaotropic to kosmotropic anion containing sodium salts. Correspondingly, a decreasing trend is observed in the thermodynamic parameters of free energy, enthalpy, and entropy. CMC and CP values are correlated with enthalpy and entropy of ion solvation, the Jones–Dole viscosity B‐coefficient, hydrodynamic radius, and polarizability of studied ions. The importance of the PPO/PEO ratio in controlling tetronic‐solvent interactions has been brought to light by the linearity of enthalpy‐entropy compensation plots.