Association properties of diblock copolymer of ethylene oxide and 1,2-butylene oxide: E 17B 12 in aqueous solution

Abstract

Copolymer E 17B 12 (E denotes OCH 2CH 2, B denotes OCH 2CH(C 2H 5), and the subscripts denote number-average chain lengths) was prepared by sequential oxyanionic polymerization and characterized by GPC (for distribution width) and NMR spectroscopy (for absolute composition and chain length). Dynamic and static light scattering and rheometry were used to characterize micelles in dilute solution and demonstrate the formation of compact micelles at low temperatures and of elongated micelles at higher temperatures, the latter being accompanied by turbidity of the solution. Rheological methods applied across a range of concentrations and temperatures served to demonstrate the formation of worm-like micelles. Gels based on entangled worm-like micelles (some of them turbid) and on packed compact micelles were identified and their properties were explored.