Effect of electric fields on the surface profiles of electrorheological suspensions
Effect of electric fields on the surface profiles of electrorheological suspensions
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DOI：
10.1016/j.colsurfa.2008.04.033
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发表时间：
2008-07
期刊：
影响因子：
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通讯作者：
Kazutoshi Tsuda;Y. Hirose;H. Ogura;Y. Otsubo
中科院分区：
文献类型：
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作者：
Kazutoshi Tsuda;Y. Hirose;H. Ogura;Y. Otsubo
研究了电场作用下石英悬浮液在梳状电极上的表面变形。在施加电场时，从光滑表面发展出具有波形的精细图案。表面轮廓可以近似为单正弦波或其叠加取决于样品的厚度。在电场作用下，SiO2悬浮液在稳态剪切下的粘度下降，在零剪切速率极限下的屈服应力下降。粘度降低可归因于粒子向一个电极的电泳迁移以及由于电极之间的粒子的链形成而导致的电流变效应的屈服应力的发展。在厚液膜中，电介质极化力占主导地位，并形成与电极间距的波长的正弦曲线。在薄膜中，电泳力占主导地位，波长与电极间距的两倍一致。在中间厚度处，表面轮廓可以由两个正弦波的叠加来表示。
The surface deformation induced in electric fields is studied on the comb pattern electrodes for silica suspensions. On the application of electric fields, a fine pattern with a waveform is developed from the smooth surface. The surface profiles can be approximated by single sinusoidal waves or their superposition depending on the sample thickness. In electric fields, the silica suspensions shows the viscosity decrease in steady shear and yield stress in the limit of zero shear rates. The viscosity decrease can be attributed to electrophoretic migration of particles to one electrode and the development of yield stress to eletrorheological effects due to chain formation of particles between electrodes. In thick liquid films, the dielectric polarization forces are predominant and the sinusoidal profiles with a wavelength of pitch of electrodes are formed. In thin films, the electrophoretic forces are predominant and the wavelength coincides with twice the pitch of electrodes. At intermediate thicknesses, the surface profiles can be expressed by a superposition of two sinusoidal waves.