Dynamic Phase Transition and Crystallization Kinetics of Polymer Colloidal Crystals

点击翻译按钮获取中文摘要

Though the phase transition and the crystallization kinetics of colloidal crystals apparently follow the classic nucleation and crystal growth theory, they are also related closely to the simultaneous synchronous fluctuation phenomena of many particles. In this study, improving the conventional indirect observation methods, the dynamic phase transitions of colloidal crystals are analyzed by the direct observation of translational diffusion in the course of crystallization by using optical microscope. 1. Monodispersed polystyrene (0.3-2μm) colloidal aqueous suspension is completely deionized by ion exchange resins for more than 6 months. 2. Time profiles of colloidal crystallization are observed by the optical microscope in originally designed cylindrical cell with platinum electrodes and a cover glass as the bottom plate. These images recorded are symbolized by the enhancement of the contrast, etc., and then they are Fourier transformed. 3. Correlation of mutual positions of colloidal particles of colloidal crystals is also analyzed using the Fourier transformation. 4. Translational diffusion is analyzed by the application of sinusoidal electric field (0.01-1Hz) to the cell. 5. Many modes of particle movement are obtained in the course of dynamic phase transition of colloidal crystals. These modes are agreed well with those already obtained by the dynamic light scattering measurements.