On-Chip Production of Size-Controllable Liquid Metal Microdroplets Using Acoustic Waves.
Micro- to nanosized droplets of liquid metals, such as eutectic gallium indium (EGaIn) and Galinstan, have been used for developing a variety of applications in flexible electronics, sensors, catalysts, and drug delivery systems. Currently used methods for producing micro- to nanosized droplets of such liquid metals possess one or several drawbacks, including the lack in ability to control the size of the produced droplets, mass produce droplets, produce smaller droplet sizes, and miniaturize the system. Here, a novel method is introduced using acoustic wave-induced forces for on-chip production of EGaIn liquid-metal microdroplets with controllable size. The size distribution of liquid metal microdroplets is tuned by controlling the interfacial tension of the metal using either electrochemistry or electrocapillarity in the acoustic field. The developed platform is then used for heavy metal ion detection utilizing the produced liquid metal microdroplets as the working electrode. It is also demonstrated that a significant enhancement of the sensing performance is achieved by introducing acoustic streaming during the electrochemical experiments. The demonstrated technique can be used for developing liquid-metal-based systems for a wide range of applications.
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA.
Shi-Yang
SY
Tang
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA.
Bugra
B
Ayan
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA.
Nitesh
N
Nama
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA.
Yusheng
Y
Bian
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA.
James P
JP
Lata
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA.|Key Laboratory of Modern Acoustics (MOE), Department of Physics, Nanjing University, Nanjing, 210093, China.
Xiasheng
X
Guo
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA.
Tony Jun
TJ
Huang
EGaIn; acoustics; electrochemistry; heavy metal ion sensing; liquid metal; microdroplets