Small angle neutron scattering study of the structure and hydration of polyoxyethylene‐block‐polyoxybutylene in aqueous solution

The micellar structure of a polyoxyethylene‐ block ‐polyoxybutylene diblock copolymer (E 18 B 10 ; E = (OCH 2 CH 2 ); B = OCH 2 CH(CH 2 CH 3 )) in water was studied by small angle neutron scattering. Results show a polydisperse spherical micelles at temperatures below 45 °C, a possible mixed phase at 45 °C and flexible worm‐like micelles at 65 °C. The spherical micelles at 25 and 35 °C have radii of 39 and 40 Å and degrees of hydration of 28% and 26%, respectively. The worm‐like micelles have a total length of approximately 1850 Å, with segment lengths of 123 Å, a core radius, R ax = 30 Å and hydration of 23%, at 65 °C.