Aqueous solutions of triblock copolymers of poly(ethylene oxide) and poly(propylene oxide) aggregate at elevated temperatures into micelles which for polymer concentrations ≥20% or more make a hard sphere crystallization to a cubic micellar crystal. Structural studies show that pressure improves the solvent quality of water, thus resulting in decomposition of the micelles and consequent melting of the miceller crystal. The combined pressure and temperature dependence reveals that (decreasing pressure) the overall entropy increases through the inverted micellar crystallization characteristic.

• Received 30 March 1993

DOI:https://doi.org/10.1103/PhysRevLett.71.1728