TOPIC： A new paradigm of materials processing 
SPEAKER： Prof. Kyung Hyun Ahn , Seoul National University

TIME：June 6 (Monday) AM10:30 
LOCATION： Room 518, Chemistry Building A (化学A楼518会议室) 
INVITER： Prof. Wei Yu (俞炜教授)
 

A new paradigm of materials processing

Kyung Hyun Ahn

School of Chemical and Biological Engineering, Seoul National University

Seoul 151-744, Korea

Email: ahnnet@snu.ac.kr

With recent advances in emerging technologies, materials design encounters new challenges. With more nano particles inside, processing experiences thinner and faster deformations than ever, which should be reflected in materials design. It happens in most emergying industries such as manufacturing of batteries, solar cells, multi-layer chips, displays, printed electronics, to list a few. In most cases, they are manufactured by coating process, which is defined as a process in which gas is replaced by liquid on a substrate. The coating process consists of three unit processes. As the materials typically contain a large amount of particles with polymers and solvents, they continuously change microstructures during preparation, flow, and even drying. However, little is known about the flow characteristics of such complex fluids and less is known about how to design and control the process. Therefore, for better control of the process and for better quality of the product, we need to understand the complex flow behavior of these complex fluids, which rarely has been studied in the past. Heterogeneity is ubiquitous in materials processing. Sometimes it appears by nature in the microstructure of a material and sometimes it is magnified during processing, which becomes more evident in highly sheared flow field in particular. Industrial coating materials such as ink, slurry and paste form heterogeneous microstructure as they contain various components. Since the material experiences high shear flow due to the small gap of tens of micrometers and the dispersion of pigment is critical to the coating performance, it is important to precisely control the flow behavior, which is highly dependent upon the rheology of the material. Therefore, it is necessary to incorporate the concept of heterogeneity into materials processing and to develop the methodology to quantitatively analyze the heterogeneous nature observed in both materials and processing. And it should be reflected in the material design. It will be a big challenge to establish a systematic protocol to characterize the materials and maintain uniform quality during manufacturing. In this talk, I will show illustrative examples that prove the heterogeneous nature in different length scales, covering the length scale from nano, micro to macro. The systems also cover a broad spectrum from electronics to energy. With many illustrative examples of both system and methodology, I will deliver my idea on the perspective and strategy of the researches, which will be a new paradigm of materials processing as well as of materials design.

Kyung Hyun Ahn

Professor

School of Chemical and Biological Engineering

Seoul National University

ahnnet@snu.ac.kr

Biography

Careers

2009.3 – present     Professor, Seoul National University

2004. 2 – 2009.3     Associate Professor, Seoul National University

2000. 6 – 2004.1     Associate Professor (BK21), Seoul National University

1994. 9 - 2000. 5     Senior Researcher, R&D Center, Samsung Cheil Industries Inc.

1993. 9 - 1994. 8     Research Associate, Institute for Chemical Researches, Kyoto University, Japan

1992. 2 - 1993. 8     Research Associate, Department of Chemical Engineering, University of Wisconsin, USA

1991. 9 - 1991.12     Research Fellow, Department of Chemistry, University of Wisconsin, USA

Education

1988. 3. - 1991. 8. Ph.D. in Seoul National University (Chemical Engineering)

1986. 3. - 1988. 2. MS in Seoul National University (Chemical Engineering)

1981. 3. - 1986. 2. BS in Seoul National University (Chemical Engineering)

Others (currently)

Vice Dean, College of Engineering, Seoul National University

Director, Center for Nano-Structured Polymer Processing Technology