Five block copolymers with three linear architectures were prepared by sequential anionic copolymerization, i.e., E102P37, E103P34, E52P34E52, E57P46E57, and P19E113P19 (where E denotes oxyethylene and P denotes oxypropylene), and the properties of their aqueous solutions were studied across a wide range of concentration. The techniques used to study micellization and micellar properties in dilute solution were static and dynamic light scattering, surface tension, and elution gel-permeation chromatography. The results showed, for example, that critical micelle temperatures for solutions of given composition fell in the order E mPn < EmPnEm < PnEmPn, in agreement with the prediction of theory. The gelation of concentrated solutions was also investigated.

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Triblock copolymer E52P34E52 was prepared by sequential anionic polymerization of propylene oxide followed by ethylene oxide. Some of this copolymer was cyclized via acetal closure to yield a cyclic diblock copolymer, cyclo-P34E104, which was characterized by gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy. Light scattering methods were used to study the micellization and micellar properties of the two copolymers:  dynamic light scattering for hydrodynamic properties of the micelles, static light scattering for micellar molar mass and critical micellization conditions. The gelation of concentrated solutions was also studied. The critical micelle concentrations (cmc) of the two copolymers were similar for solutions at 40−50 °C, but the temperature dependence of the cmc was smaller for the linear copolymer. The cyclic copolymer in solution at 50−55 °C formed micelles with larger association numbers and hard-sphere volumes than its linear triblock counterpart.

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