| Research Abstract |
Using light scattering measurements of polystirene/polybutadiene/DOP semidilute solutions under shear flow, we observed shear-induced homogenization and obtained the composition dependence of the critical shear rate. In the string phases, which are observed in the steady state of two-phase region under shear flow, we confirmed that shear flow strongly suppressed undulation of the interface. We observed the effect of oscillatory shear flow on the spinodal decomposition of polybutadiene/polyisoprene mixtures and stirene-butadiene rubber/butadiene mixtures.
To obtain fundamental knoeledge on the polymers under shear flow, we observed light scatterng and microscopic images of high molecular weight polystirene/DOP and high molecular weight polyethylene/paraffin semidilute solutions. We obtained the typical butterfly type scattering patterns by SALS and the concentration fluctuations by microscopy which caused such scattering patterns. In the high shear rate regime where we observed rheological and scattering anomalies we confirmed that the string phase like the above-mentioned occurred.
To observe orientation and deformation of microdomain structures of block copolymers under shear flow, we constructed the control system of shear deformation apparatus and two-dimensional X-ray scattering detector (imaging plate). Using this system, deformation and relaxation of orientation in spherical and lamellae microdomains under oscillatory shear flow have been clarified.
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