Micellization and Clouding Behavior of EO–PO Block Copolymer in Aqueous Salt Solutions

• DOI: 10.1007/s11743-009-1127-5
• Publication Date: 2009-05-20T11:35:58Z
• Authors: Keyur Patel; Bhavesh Bharatiya; Yogesh Kadam; Pratap Bahadur
• Keywords: Hofmeister series; Cloud point; Thermodynamics of micellization; Aggregation number; Krafft temperature; Hydrodynamic radius

Abstract Aqueous solution properties of polyethylene oxide– block ‐polypropylene ‐polyethylene oxide TBP [(PEO) 103 (PPO) 39 (PEO) ] were studied in the presence sodium salts with different anions (NaI, NaBr, NaCl, NaF, Na 2 SO 4 , 3 PO ) to investigate unimer‐to‐micelle transition [critical micelle concentration (CMC), critical micellization temperature (CMT)], size and phase separation (cloud point). This TBP, due its very hydrophilic (80% PEO) nature does not form micelles at ambient temperatures. Micellization can be induced much below CMT water on addition having anions. Analytical methods viz. fluorescence, FTIR dynamic light scattering (DLS) used monitor salt‐induced micellization. The hydration respective anion resultant contribution salting‐out effect was found governing factor promoting salt decreases CMC, temperature. affect aggregation process agreement an order mentioned Hofmeister series.