We report an experimental study on shape deformations of ternary vesicles undergoing phase separation under an osmotic pressure difference. The phase separation on various shape vesicles causes unique shape-deformation branches. In the domain coarsening stage, prolate, discocyte, and starfish vesicles show a shape convergence to discocytes, whereas a pearling instability is observed in tube vesicles. In late stages, the domains start to bud towards the inside or outside of the vesicle depending on the excess area. We discuss the deformation branches based on the membrane elasticity model.

Based on experimental findings, a mechanism of structural formation during the induction period of polymer crystallization is proposed. Recently we have found that, during the induction period of crystallization of poly(ethylene terephthalate) before crystal nuclei are produced, a correlation peak appears in small-angle x-ray scattering, and grows in intensity and position with time while the crystallization temperature is kept constant. The position of this peak is of course different from that of the intercrystallite correlation peak, the so-called long-period peak, in the crystallization stage; the former peak position is considerably lower than the latter. Surprisingly the time evolution of the former peak obeys the spinodal decomposition kinetics. In this study the cause for such a phenomenon is investigated from the viewpoint of the orientation fluctuations of rigid molecular segments using depolarized light scattering as well as small-angle neutron scattering (SANS). The depolarized light-scattering measurements indicate that during the induction period the parallel ordering of the rigid molecular segments occurs and this ordering process agrees with the spinodal decomposition kinetics in the isotropic-nematic transition theory proposed for stiff polymers by Doi et al. Further, the critical concentration of rigid segments at which the isotropic state becomes unstable is discussed using the molecular stiffness or the persistence length estimated from the molecular conformations observed by an isotope-labeling method for SANS.

The kinetics during the induction period of polymer crystallization is studied by means of depolarized light scattering measurements. The spinodal decomposition during this period is shown to be caused by orientation fluctuations of polymer segments. Time evolution of these orientation fluctuations can be described by the spinodal decomposition kinetics in terms of transformation from the isotropic to nematic phase proposed by Doi et al.