Research Highlights

Prof. Dong Sung Kim and Students Discover Water Flow Includes Various Characteristics

2015-10-22 352
Prof. Dong Sung Kim with students Dongwhi Choi and Donghyeon Lee

Prof. Dong Sung Kim with students Dongwhi Choi and Donghyeon Lee (Dept. of Mechanical Engineering) have published a paper in Scientific Reports on the evaluation strategy for various liquid characteristics.
When liquid in contact with a solid surface detaches itself, the net electrical charge is spontaneously generated on the solid surface by a phenomenon called “solid-liquid contact electrification”. The concept of solid-liquid electrification was first observed in an article that was written by Prof. Dong Sung Kim and Dongwhi Choi and published in Scientific Reports (2013) entitled “Spontaneous electrical charging of droplets by conventional pipetting” and Langmuir (2014) entitled “A Zeta (ζ)-Pipet Tip to Reduce the Spontaneously Induced Electrical Charge of a Dispensed Aqueous Droplet”. The article was featured as an American Chemical Society (ACS) Editors’ Choice in June 2014.
Since the amount of net electrical charge is highly dependent on the characteristics of the liquid (i.e. electrolyte concentration and acidity (pH)), these characteristics could be easily evaluated by utilizing the net electrical charge generated on the solid surface. It is the first utilization of the spontaneously generated electrical charge to be characterized. The characterization platform utilizing this pioneering approach exhibits several advantages including simple operation, precise measurement, and cost-effectiveness. The concept is further extended as a development of a self-powered gas slug (similar with a gas bubble) sensor, which can detect and count the number of tiny gas slugs in a gas-liquid two phase flow.
What is notable about the article is that the co-first author of the article, Donghyeon Lee, is a fourth year undergraduate student in the Dept. of Mechanical Engineering at POSTECH. Along with mechanical engineering graduate student Dongwhi Choi, Mr. Lee performed many experiments and contributed to the manuscript under the guidance of Prof. Dong Sung Kim.
This work was supported by the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI) funded by the Ministry of Health & Welfare and a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP).