Aqueous gels of triblock copolymers of ethylene oxide and 1,2-butylene oxide (type BEB) studied by rheometry

A triblock copolymer of ethylene oxide and 1,2-butylene oxide with hydrophilic central block and hydrophobic end blocks, denoted B 10E227B10, was prepared and characterised. The frequency dependence of dynamic modulus was determined for micellar solutions in the concentration range of 8-20 wt.-% and the temperature range of 5-70°C, and the fluid/gel diagram was established. The results were combined with those reported previously for copolymers B12E227B12 and B12E114B12 to obtain insight into the effect of B-block and E-block length on the rheological properties of systems of this type. The results are discussed in terms of micelles forming bridged networks and, at higher concentrations, packing in structured gels. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.