Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7138428 | Sensors and Actuators A: Physical | 2012 | 8 Pages |
Abstract
We show that pearl chains of gold nano-particles (Au NPs) are formed consistently between microelectrodes by combining microspotting and dielectrophoretic (DEP) techniques. Experimental results on various sized Au particles and DEP parameters, including voltage and frequency, are reported in this paper to explore the critical parameters in controlling the pearl chain formation (PCF) process between microelectrodes. PCF is observed from 10Â kHz to 5Â MHz for 100Â nm diameter Au NPs, and 100Â kHz to 10Â MHz for 10Â nm Au NPs. Variations in formation rate are detected when the applied voltage and particle size varies. At higher voltages, PCF occurs at a higher rate and the formation time decreases. The optimum frequency for Au NPs PCF shifts to a higher frequency region when the particle size decreases. Theoretical analysis is carried out by calculating the DEP force with AC electrokinetics to explain the observations at DEP frequencies ranging from 10Â Hz to 10Â MHz. Finally, Au NP chains formed between the microelectrodes are shown to vary in resistance consistent with predictions for a simplified model of an impinging jet system, indicating that these Au particle sensors could potentially be used to precisely measure localized temperatures and other localized thermal phenomena.
Related Topics
Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Siu Ling Leung, Minglin Li, Wen J. Li, John D. Mai,