Small amplitude oscillatory rheology is employed to investigate the linear viscoelastic behavior of polystyrene / poly(vinyl methyl ether), PS/PVME, as a function of temperature.
The relation between rheology and the time dependent morphology of a phase-separation was also investigated by heating a sample from the single-phase (at 90oC) into the two-phase regime (at
130oC,16oC above the LCST) and maintaining the temperature while measuring the evolution of the dynamic moduli G’ and G”. The phase transition temperature of PS-280K/PVME-90K and PS-280K
F17/PVME-90K (17-arm fluorinated) are determined by plotting GNo as a function of temperature between the 80oC-130oC. The two systems were to have dramatic differences which could be related to the
different rheological properties. In addition, they responded differently to applied shear rate at different Weisseberg numbers ( Wi = 0.5, 2.0, 5.0, 7.0).
Publisher
Cornell Center for Materials Research
Date
2005-08-17
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Additional Notes
Acknowledgements: This work was supported by the Cornell Center for Materials Research and the National Science Foundation
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View Generic Document: Shear-induced Demixing and Phase-Separation Behavior in Polystyrene -Poly (vinyl methyl ether) ( PS/PVME) System 