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 L 64: 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 NM R. At low copolymer concentrations, micelles coexisted with unimers an d the micellar size increased with increasing amount of water in the m ixture. Large aggregates were formed at higher copolymer concentration s. The size and the amount of the large aggregates increased with incr easing amount of water in the mixtures, and increasing copolymer conce ntration. The solubilized water can be classified into free-water(form ing hydrogen bond with water) and bound-water(forming hydrogen bond wi th EO units). The environment of EO units changed with the amount of s olubilized water. The conformation of the copolymer remained essential ly the same before and after micellization and did not change with the amount of solubilized water.