Institute of Applied Mechanics, National Taiwan University, Taipei, 10617, Taiwan, Republic of China.
Electrophoresis. 2020 Jan;41(1-2):137-147. doi: 10.1002/elps.201900345. Epub 2019 Nov 11.
A method is proposed for measuring the real part of the Clausius-Mossotti factor ( ) of dielectrophoresis for Brownian particles based on a solution of the Smoluchowski equation using a designed polydimethysilloxane microchannel with planar hyperbolic electrodes on its glass substrate. An approximate two-dimensional spring-like dielectrophoretic force is generated in the device, and the data necessarily measured is the time evolution of the in-plane particle displacement undergoing confined Brownian motion. Validity of the measurement was checked against the zeta potentials in the literature based on the classical theory of surface conductance using polystyrene particles of size of one micron. As the dielectrophoretic force depends on , which is usually unknown for bio-particles and some engineered particles, and is seldom measured; this study is important from the academic point of view and could be helpful for the manipulation and characterization of sub-micron particles using dielectrophoresis. Extension of the method to the measurement of permanent dipole moment and total polarizability of particle was developed theoretically and discussed by incorporating an optical tweezer into the present device.
提出了一种基于设计的聚二甲基硅氧烷微通道和玻璃衬底上的平面双曲电极，利用 Smoluchowski 方程的解来测量布朗粒子的介电泳 Clausius-Mossotti 因子（ ）实部的方法。在该装置中产生近似二维的弹簧状介电泳力，并且必须测量的是在受限布朗运动下的平面粒子位移的时间演化。通过使用尺寸为一微米的聚苯乙烯粒子，根据基于表面电导的经典理论，用文献中的 ζ 电位检查了测量的有效性。由于介电泳力取决于 ，对于生物粒子和一些工程粒子， 通常是未知的，并且很少被测量；因此，从学术角度来看，这项研究很重要，并且可能有助于使用介电泳来操纵和表征亚微米粒子。通过将光学镊子结合到现有设备中，从理论上扩展了该方法，并讨论了测量粒子的永久偶极矩和总极化率的方法。
