Influence of Adding Unfunctionalized PEO on the Viscoelasticity and the Structure of Dense Polymeric Micelle Solutions Formed by Hydrophobically End-Capped PEO

International audienceHydrophobically end-capped poly(ethylene oxide) (PEO) is a highly asymmetric diblock copolymer that forms spherical micelles in water resembling multiarm star polymers. The dynamic mechanical properties of these polymeric micelles were studied in the absence and in the presence of unfunctionalized PEO chains as a function of concentration and temperature. A discontinuous reversible liquid-solid transition was observed below a critical temperature (T-c). Addition of linear chains led to a decrease of T-c and a strong slowing down of the kinetics of the transition close to T-c. Flow measurements of the solid showed a steep power law decrease of the flow rate with decreasing stress. For a given stress the flow rate increased after addition of linear chains, but the stress dependence of the flow rate remained the same. Dynamic and static light scattering measurements were done to investigate the influence of adding linear chains on the osmotic compressibility and the cooperative diffusion of polymeric micelle solutions