Abstract
The self-assembly behaviour of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly (ethylene oxide) copolymers, (EO)(13)(PO)(30)(EO)(13)(Pluronic L64), and (EO)(70)(PO)(30)(EO)(70) (Pluronic F68) in water and in p-xylene has been elucidated by using viscosity and dynamic light scattering measurements to investigate the effects of hydrophilic chains length on their conformational changes. The viscosity measurements were performed for a range of temperature varying from 27 degrees C to 60 degrees C and concentration from4 to 60 mg/ml. The variation of the viscosity and the conformational changes in aqueous solution depends on the kinds of interactions and the balance between excluded volume effects and hydrophobic interactions. Some dynamic light scattering measurements were also performed at room temperature for the same range of concentration to provide more information on the micellar structures in aqueous and organic solution.