George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Anal Chem. 2010 Mar 15;82(6):2204-12. doi: 10.1021/ac901287z.
This article presents results of detailed and direct real-time observations of the wide variety of SnO(2) nanobelt motions induced by ac dielectrophoresis (DEP) in an innovative microfluidic setup. High ac electric fields were generated on a gold microelectrode (approximately 20 microm electrode gap) array, patterned on a glass substrate and covered by a approximately 10 microm tall polydimethylsiloxane (PDMS) microchannel. Ethanol suspended SnO(2) nanobelts were introduced into the microchannel, and the DEP experiments were performed. Negative DEP (repulsion) of the nanobelts was observed in the low-frequency range (<100 kHz) of the applied electric field, which caused rigid body motion as well as deformation of the nanobelts. The negative DEP effect observed in ethanol is unusual and contrary to what is predicted by the Clausius-Mossotti factor (using bulk SnO(2) conductivity and permittivity values) of the dipole approximation theory. In the high-frequency range (approximately 1-10 MHz), positive DEP (attraction) of the nanobelts was observed. Pearl chain formation involving short nanobelts and particles was also observed in the two DEP regimes.
本文介绍了在创新的微流控装置中通过交流介电泳（DEP）诱导 SnO(2)纳米带的各种广泛运动的详细和直接实时观察结果。在金微电极（约 20 微米电极间隙）阵列上产生了高交流电场，该阵列图案化在玻璃基底上，并由约 10 微米高的聚二甲基硅氧烷（PDMS）微通道覆盖。将悬浮在乙醇中的 SnO(2)纳米带引入微通道，并进行 DEP 实验。在施加电场的低频范围（<100 kHz）观察到纳米带的负 DEP（排斥），这导致了刚体运动以及纳米带的变形。在乙醇中观察到的负 DEP 效应是不寻常的，与偶极近似理论的克劳修斯-莫索蒂因子（使用体相 SnO(2)电导率和介电常数值）的预测相反。在高频范围（约 1-10 MHz），观察到纳米带的正 DEP（吸引）。在两种 DEP 状态下，还观察到涉及短纳米带和颗粒的珍珠链形成。
