Palapati N K R, Pomerantseva E, Subramanian A
Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
Nanoscale. 2015 Feb 21;7(7):3109-16. doi: 10.1039/c4nr06303a.
This paper presents the quantitative relationship between the control parameters of a dielectrophoretic (DEP) force field and the resulting electrokinetic region of influence experienced by individual nanowires (NWs) in colloidal suspensions. Our results show that DEP operation at sub-crossover frequencies, which are defined as frequencies slightly below the transition from positive-to-negative DEP, offers a suitable but previously unexplored performance regime for single NW manipulation and assembly. The low-magnitude DEP forces at these frequencies, which are estimated to be 8 orders of magnitude smaller as compared to near-DC frequencies, provide an efficient avenue to controllably extend electrokinetic influence on suspension volumes that present isolated NWs. These results are demonstrated using α-phase manganese dioxide NWs as a model one-dimensional construct. Based on experimentally extracted values for the NW intrinsic conductivity and dielectric permittivity, we employ computational models to explain each of the performance regimes observed in this nanoassembly system. In addition, we use a new approach to estimate the concentration of a NW suspension from experimentally observed data for deposition yields.
本文介绍了介电泳（DEP）力场的控制参数与胶体悬浮液中单个纳米线（NWs）所经历的电动力学影响区域之间的定量关系。我们的结果表明，在亚交叉频率下进行DEP操作（亚交叉频率定义为略低于从正DEP转变为负DEP的频率），为单个NW的操纵和组装提供了一种合适但此前未被探索的性能机制。与近直流频率相比，这些频率下的DEP力幅度较低，估计要小8个数量级，这为可控地扩展对存在孤立NW的悬浮液体积的电动力学影响提供了一条有效途径。使用α相二氧化锰NW作为一维模型结构证明了这些结果。基于通过实验提取的NW本征电导率和介电常数的值，我们采用计算模型来解释在这个纳米组装系统中观察到的每种性能机制。此外，我们使用一种新方法，根据实验观察到的沉积产率数据来估计NW悬浮液的浓度。
