Novel amphiphilic graft copolymers composed of a polyisoprene (PIP) backbone with Pluronic side chains, polyisoprene-g-Pluronic,have been synthesized using a “graft onto” technique. Small-angle neutron scattering (SANS) has been used to characterize the conformation of the P123 and P103 Pluronic graft copolymersin selective solvents such as ethanol and hexaneand in a non-selective solvent, THF. The results indicated that, in a selective solvent for the side chain Pluronics (e.g. ethanol), “crew-cut” micelles were formed with a large core of radius ~ 120 Å; data were fitted with a core-shell model. In a good solvent for the backbone (e.g. hexane) “flower-like” micelles were formed with a small inner radius of ~ 64 Å. In the non-selective solvent a swollen polymer coilwas found, which was described using the Guinier-Debye model. As THF/ethanol, and THF/hexane can be prepared in any ratio, it was possible to vary the solvent composition gradually in order to study the transition from swollen coil to micelle. When going from 100% THF to 100% ethanol, the transition to micellar behaviour was observed at a ratio of 20:80 (v/v %) THF/ethanol for both grafted copolymers and 40:60 (v/v %) THF/hexane for grafted P123 copolymers.

Generated automatically with Publist v. 1.3b

Last edited: Friday September 10, 2010

Valid XHTML 1.1 Valid CSS 2