Faculty of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe, Mizuho, Nagoya, Aichi 467-8603, Japan.
J Colloid Interface Sci. 2012 Mar 15;370(1):39-45. doi: 10.1016/j.jcis.2011.12.071. Epub 2012 Jan 8.
We examine the compression of charged colloidal crystals under the influence of gravitational force by monitoring the spatiotemporal variations of Bragg diffraction from the crystal lattice. We use the dilute aqueous dispersions of colloidal silica particles (diameter=216 nm, charge number=733, a particle volume fraction φ=0.06) in the presence of 5-15 μM sodium chloride. The sedimentation profiles of the colloidal crystals along the crystal height are determined by in situ fiber optics reflection spectroscopy. The time evolutions of the sedimentation profiles are calculated by numerical simulations based on a phenomenological continuum model that explicitly incorporates the electrostatic interparticle interactions. The simulation results correctly describe the experiments at sufficiently high ionic strength.
我们通过监测晶格的布拉格衍射的时空变化来研究在重力作用下带电胶体晶体的压缩。我们使用直径为 216nm、电荷数为 733、颗粒体积分数φ为 0.06 的胶体二氧化硅颗粒在 5-15μM 氯化钠存在下的稀水溶液。通过原位光纤反射光谱法确定胶体晶体沿晶体高度的沉降分布。根据明确包含静电粒子间相互作用的唯象连续体模型的数值模拟计算沉降分布的时间演化。模拟结果在足够高的离子强度下正确描述了实验。
