February 9, 2018
Speaker: Chuanhua Duan
Affiliation: Boston University
Nanoporous media and membranes play important roles in a wide range of industrial and energy applications including batteries/fuel cells, materials processing, fluid separation, and sensing. Further development of nanoporous media and membranes requires thorough understanding of their transport properties. However, the current approach of studying nanoporous media and membranes in their final applications, e.g. in the form of a membrane for water purification, limits our understanding of fundamental mass transport inside due to the structure complexities, and therefore limits us from maximizing their performance in existing applications and the development of new applications. An alternative approach to study nanoporous media and membranes is to study them in the form of their basic constituents, e.g. single nanopores/nanotubes/nanochannels.
This new approach, now referred as the nanofluidic approach, opens new opportunities to further develop nanoporous media and membranes and has attracted great attention over the last ten years. In this talk, I will present several of our recent works on exploring new fundamentals and applications of nanoporous media and membranes using novel nanofluidic platforms. I will start with a study of understanding drying kinetics in nanoporous media using simple transparent planar nanochannels and show how different drying behaviors and vapor/liquid transport inside the nanochannels can affect drying kinetics. I will then introduce our recent efforts on exploring ultimate water capillary evaporation in nanoporous membranes using single nanochannels/nanopores. I will demonstrate that the ultimate evaporation fluxes can break down the limits predicated by the classical Hertz-Knudsen equation by an order of magnitude and report the dependence of the kinetic-limited evaporation flux on confinement, temperature and humidity. Finally, I will share our latest work on studying fast water transport in single graphene nanochannels. Quantitative understanding of water slippage on graphene surface and its effect on water permeability and application of GO membranes will be discussed.
Dr. Chuanhua Duan earned his B.S. and M.S. degrees in Engineering Thermophysics from Tsinghua University in 2002 and 2004, respectively. He obtained his Ph.D. in Mechanical Engineering from the University of California at Berkeley in 2009 under the guidance of Prof. Arun Majumdar. After staying in Berkeley for two more years as a postdoctoral researcher at the Lawrence Berkeley National Laboratory, Dr. Duan joined the Department of Mechanical Engineering at Boston University as an assistant professor in 2012. He is currently leading the Nanoscale Energy-Fluids Transport Laboratory at BU ME. Among his honors, Dr. Duan received the National Science Foundation Early Faculty Career Development Award (CAREER) in 2017 and the American Chemistry Society Petroleum Research Fund Doctoral New Investigator award in 2013. His research focuses on the study of micro- and nanofluidic transport phenomena and the development of new fluidic devices/approaches for applications in healthcare, energy systems, and thermal management.