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中文核心期刊

受限分散体系中粒子扩散特性的研究

The study of diffusion coefficient of micro-particles in confined dispersion

  • 摘要: 当微小粒子被限制在两个距离很近的平行平面之间时,其扩散将不同于它在无限空间中的自由扩散. 利用光镊和CCD图像相关处理系统,直接测量了直径1μm的聚苯乙烯小球在不同高度,一定时间间隔内,沿着平行玻片表面方向上布朗运动的距离,并由此得到了样品池上下两个平行表面对分散体系分散相小球扩散特性的影响. 还利用小球偏离物镜焦平面不同距离时的成像状况,用相关运算法确定了小球在纵向上的位置,实现了小球扩散特性与小球在样品池中的纵向位置的关系的研究.

     

    Abstract: The diffusion characters of particles constrained between two shortly separated flat walls are different from those of particles in the infinite space. In this paper, constrained diffusion of an isolated micro-sphere (about 1μm in diameter, Polystyrene) confined between two parallel flat walls was studied using video microscopy combined with optical tweezers by measuring the distance of Brownian motion of a sphere within a period of time. We also developed a method of measuring the distance of vertical motion of a sphere based on the correlation analysis of the sphere image, which decreases the measurement error, by which the relation between diffusion character of a sphere and its distance to the bottom of the sample cell was experimentally studied.

     

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