SMALL-ANGLE NEUTRON-SCATTERING STUDY OF POLYMERIC MICELLAR STRUCTURES

Polymeric micellar structures formed by a PEO-PPO-PEO copolymer in o-xylene in the presence of water were investigated by small-angle neutron scattering. In order to reveal the detailed micellar structure, different contrasts among the micellar core, the micellar shell, and the dispersing medium (background) were constructed by selectively changing the protonated/deuterated combination of water and xylene. The micellar structure could be well described by a core-shell structure with the scattering behavior of the micellar shell being very similar to that of a star polymer. The solubilized water existed not only in the micellar core but also in the micellar shell. The volume fraction of copolymer segments in the micellar shell was rather low, being of the order of 0.2. There seemed to be no sharp interface between the micellar con and the micellar shell.