title: Hydrodynamic dispensing and electrical manipulation of attolitre droplets.
abstract: Dispensing and manipulation of small droplets is important in bioassays, chemical analysis and patterning of functional inks. So far, dispensing of small droplets has been achieved by squeezing the liquid out of a small orifice similar in size to the droplets. Here we report that instead of squeezing the liquid out, small droplets can also be dispensed advantageously from large orifices by draining the liquid out of a drop suspended from a nozzle. The droplet volume is adjustable from attolitre to microlitre. More importantly, the method can handle suspensions and liquids with viscosities as high as thousands mPa s markedly increasing the range of applicable liquids for controlled dispensing. Furthermore, the movement of the dispensed droplets is controllable by the direction and the strength of an electric field potentially allowing the use of the droplet for extracting analytes from small sample volume or placing a droplet onto a pre-patterned surface.
authors: Institute of Chemistry, Center of Interface Sciences, Faculty of Mathematics and Science, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, Germany.
authors: Yanzhen
authors: Y
authors: Zhang
authors: Guangdong Province Key Laboratory of Precision Equipment and Manufacturing, School of Mechanical and Automation Engineering, South China University of Technology, 510640 Guangzhou, China.
authors: Benliang
authors: B
authors: Zhu
authors: Department of Mechanical and Electronic Engineering, College of Mechanical and Electronic Engineering, China University of Petroleum, Qingdao 266580, China.
authors: Yonghong
authors: Y
authors: Liu
authors: Institute of Chemistry, Center of Interface Sciences, Faculty of Mathematics and Science, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, Germany.
authors: Gunther
authors: 0000-0002-6884-5515
authors: G
authors: Wittstock