STRUCTURE AND DYNAMICS OF COPOLY(OXYETHYLENE-OXYPROPYLENE-OXYETHYLENE) IN O-XYLENE/WATER MIXTURES

The structure and dynamics of supramolecules of a triblock copolymer, copoly(oxyethylene-oxypropylene-oxyethylene), also known as PLURONIC L64: PEO(13)PPO(30)PEO(13), in o-xylene/water mixtures were studied by means of dynamic light scattering, small-angle X-ray scattering and NMR. At low copolymer concentrations, micelles coexisted with unimers and the micellar size increased with increasing amount of water in the mixture. Large aggregates were formed at higher copolymer concentrations. The size and the amount of the large aggregates increased with increasing amount of water in the mixtures, and increasing copolymer concentration. The solubilized water can be classified into free-water(forming hydrogen bond with water) and bound-water(forming hydrogen bond with EO units). The environment of EO units changed with the amount of solubilized water. The conformation of the copolymer remained essentially the same before and after micellization and did not change with the amount of solubilized water.