Efficient particle and droplet manipulation utilizing the combined thermal buoyancy convection and temperature-enhanced rotating induced-charge electroosmotic flow

Kailiang Zhang; Yukun Ren; Ye Tao; Xiaokang Deng; Weiyu Liu; Tianyi Jiang; Hongyuan Jiang

doi:10.1016/j.aca.2019.10.044

Efficient particle and droplet manipulation utilizing the combined thermal buoyancy convection and temperature-enhanced rotating induced-charge electroosmotic flow

Anal Chim Acta. 2020 Feb 1:1096:108-119. doi: 10.1016/j.aca.2019.10.044. Epub 2019 Oct 23.

Authors

Kailiang Zhang¹, Yukun Ren², Ye Tao³, Xiaokang Deng¹, Weiyu Liu⁴, Tianyi Jiang¹, Hongyuan Jiang⁵

Affiliations

¹ School of Mechatronics Engineering, Harbin Institute of Technology, Harbin, Heilongjiang, 150001, PR China.
² School of Mechatronics Engineering, Harbin Institute of Technology, Harbin, Heilongjiang, 150001, PR China; School of Engineering and Applied Sciences, Harvard University, Cambridge, USA. Electronic address: rykhit@hit.edu.cn.
³ School of Mechatronics Engineering, Harbin Institute of Technology, Harbin, Heilongjiang, 150001, PR China; School of Engineering and Applied Sciences, Harvard University, Cambridge, USA.
⁴ School of Electronics and Control Engineering, Chang'an University, Xi'an, Shanxi, 710064, PR China.
⁵ School of Mechatronics Engineering, Harbin Institute of Technology, Harbin, Heilongjiang, 150001, PR China. Electronic address: jhy_hit@hit.edu.cn.

PMID: 31883577
DOI: 10.1016/j.aca.2019.10.044

Abstract

Efficient granular sample manipulation is crucial for various microfluidic-based applications such as material synthesis and drug delivery. Herein we present a novel method to efficiently manipulate microbeads and droplets using the combined thermal buoyancy convection and temperature-enhanced rotating induced-charge electroosmotic flow. Within the granular fluid, a pair of counter-rotating microvortices is formed above the floating electrode, leading to the formation of a flow stagnation region at the bottom center. Granular samples then can be effectively transported to this region by the Stokes drag, and the concentration performance can be flexibly manipulated by adjusting the energization strategies of the chip. The contributions of fluid convection, dielectrophoresis, thermophoresis, and gravity force to particle migration are first studied and compared, proving that the convection flow and gravity force are mainly responsible for particle migration and deposition respectively. Then the systematic enriching experiments of 4-μm silica particles demonstrate that the particle migration velocity can be highly improved by the combined thermal-electrical field. Finally, the effective concentration of nanocopper particles and the assembly of oil-in-water/water-in-oil-in-water droplets indicate that this approach is capable of manipulating diverse granular samples. Therefore, this strategy can be attractive for lots of microfluidic-based applications because of its high efficiency and simplicity.

Keywords: Assembly; Combined thermal-electrical field; Concentration; Electroosmotic flow; Particle and droplet manipulation; Thermal buoyancy convection.