LAMELLAR STRUCTURE OF BLOCK-COPOLYMER POLY(OXYETHYLENE OXYPROPYLENE OXYETHYLENE) IN XYLENE WATER MIXTURES

Synchrotron small angle X-ray scattering (SAXS) was used to study the supramolecular structure formed by a block copolymer, Pluronic L64 (PE O13PPO30PEO13), in xylene/water mixtures. Lamellar structure was obser ved at very high polymer concentrations (e.g., C-degree > 0.53 g/mL). The lamellar spacing was determined by the amount of solubilized water and the copolymer concentration, with the amount of water playing a m ore important role on the lamellar spacing than the copolymer concentr ation. The lamellar spacing was almost independent of temperature. How ever the scattering peak became broader with increasing temperature, i mplying that the micellar size became smaller. Experimental data could be fitted by the Teubner-Strey model, and the resulting periodicity w as in good agreement with the lamellar spacing derived by using the Br agg equation.