George W Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Nanotechnology. 2010 Aug 13;21(32):325501. doi: 10.1088/0957-4484/21/32/325501. Epub 2010 Jul 21.
A novel experimental approach is used for studying the response of ethanol-suspended SnO(2) nanobelts under the influence of low frequency ac electric fields. The electrically generated forces are estimated by analyzing the angular motion of the nanobelt, induced by repulsive forces originating predominantly from negative dielectrophoresis (DEP) on planar microelectrodes. The nanobelt motion is experimentally recorded in real time in the low frequency range (<100 kHz) and the angular velocities are calculated. A simple analytical model of force balance between the electrical forces and fluidic drag for long nano-objects is developed and used to deduce estimates of the frequency-dependent DEP force and torque magnitudes from the angular velocity data. Additional experiments, performed in a parallel plate electrode configuration in a fluidic channel to investigate the effect of dc and very low frequency ac (approximately Hz) electric fields, indicate the presence of electrophoresis in the ethanol-suspended SnO(2) nanobelts. The experimentally observed nanobelt motion is analyzed using the equation of motion, and an order-of-magnitude estimate of the nanobelt surface charge density is obtained.
采用一种新颖的实验方法研究了在低频交流电场作用下乙醇悬浮 SnO(2)纳米带的响应。通过分析纳米带在平面微电极上主要源于负介电泳（DEP）的排斥力引起的角运动，估算出电场产生的力。在低频范围内（<100 kHz）实时实验记录纳米带的运动，并计算角速度。针对长纳米物体建立了一个简单的电动力与流体阻力之间的力平衡分析模型，并从角速度数据中推导出频率相关的 DEP 力和力矩的估计值。在流体通道中的平行板电极配置中进行的附加实验研究了直流和极低频率交流（约 Hz）电场的影响，表明在乙醇悬浮的 SnO(2)纳米带中存在电泳现象。使用运动方程分析实验观察到的纳米带运动，并获得纳米带表面电荷密度的数量级估计。
