Materials Science and Engineering Colloquium - Yang
Date: November 14, 2014 from 11:00 am to 12:00 pm EST
Location: Columbia University, Morningside Campus
S.W. Mudd, Room 214
Contact: For further information regarding this event, please contact James Im by sending email to ji12@columbia.edu or by calling 212-854-8341.
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Dr. E. H. Yang

Professor of Mechanical Engineering Department at Stevens Institute of Technology

"Utilizing Engineered Carbon Surfaces - Fundamentals and Applications"

Abstract: Our group explores and utilizes the surface properties of carbon-based materials with applications to energy and the environment. I will present two different topics. First topic is our development of the seamless growth of carbon nanotubes on graphene for energy storage applications. Here, the full utilization of a graphene-carbon nanotube construct requires maintaining the integrity of the graphene layer during the nanotube growth step. We exhibit controlled carbon nanotube growth atop graphene substrates where the reaction between the source hydrocarbon gas decomposition and carbon saturation into and precipitation from the catalyst nanoparticles shifts toward carbon nanotube growth rather than graphene consumption. We demonstrate that our low-temperature growth suppresses undesirable catalytic hydrogenation and dramatically reduces the etching of the graphene layer to exhibit graphene-carbon nanotube hybrids with continuous, undamaged structures. We also study the growth of graphene domains, showing that the underlying Cu crystal orientation has a major influence on the growth kinetics, from nucleation to diffusion - an important finding towards tailoring properties of graphene via substrate engineering. The second topic is our investigation into tunable wetting of conjugated polymer surfaces for microfluidics-based separation and lab chip applications. We demonstrate a tunable wetting mechanism on a smart polymer: dodecylbenzenesulfonate-doped polypyrrole (PPy(DBS)), and probe fundamental mechanisms related to the electrochemical transport and reversible wetting states of PPy(DBS) upon continuous reduction and oxidation reactions. Ultimately, this project is expected to enable the development of lab-on-a-chip devices which can bi-directionally transport liquid droplets at voltages which are of much lower orders of magnitude than existing techniques. In addition, we look into other applications including chemical separation and antimicrobial devices based on engineered conjugated polymer surfaces.

Bio: Dr. E. H. Yang is a Professor of the Mechanical Engineering Department at Stevens Institute of Technology. He received his B.S, M.S., and Ph.D. degrees from Ajou University, Korea. After his postdoctoral training at University of Tokyo and at California Institute of Technology, Dr. Yang joined NASA's Jet Propulsion Laboratory where he was a Senior Member of the Engineering Staff. He has been the recipient of a number of awards, including NASA ICB Space Act Awards, Bonus (Level B and C) Awards and a number of Class 1 NASA Tech Brief Awards. In recognition of his excellence in advancing the use of MEMS-based actuators for NASA's space applications, he received the prestigious Lew Allen Award for Excellence at JPL in 2003. Since joining Stevens in August 2006, he has established novel research programs focused on investigating wetting properties of conjugated polymers and growth of 1D/2D nanostructures for sensing and energy applications. His scholarly leadership has been recognized by peers. Examples of these efforts include being appointed as an Associate Editor and/or Editorial Board of several journals including the IEEE Sensors Journal, and being elected as the Division Chair of the ASME MEMS Division. As Principal Investigator he has been responsible for obtaining extremely competitive research funding from several federal agencies including NSF, AFOSR, US Army, NRO, NASA and DARPA (including 6 NSF and 3 AFOSR grants, and 5 NASA and 3 NRO contracts) with the total amount exceeding $7M. Dr. Yang holds over 12 patents issued or pending. Dr. Yang is the director of the Micro Device Laboratory, a Stevens's multi-user microfabrication facility.

Host: James Im