Atomically thin membranes: development and applications
Guest Speaker：Assoc. Prof. Chi David Cheng，UNSW Sydney, Australia
Inviter: Assoc. Prof. Zhigang Hu
Date&Time: Friday, 27.Dec., 13:30-15:00
Venue: Yiucheng Lecture Hall (500) , Xu Zuyao Building
Biography:
Dr. Chi (David) Cheng is a Senior Lecturer and ARC Future Fellow in Chemical Engineering at UNSW Sydney, where he established the Nanofluidics and Advanced Separations Laboratory in 2023. He also serves as the Manager of the UNESCO Centre for Membrane Science and Technology at UNSW. Previously, he was a Postdoctoral Associate and Research Scientist in Mechanical Engineering at MIT (2017–2022) and worked in the R&D division of DuluxGroup Australia (2016–2017). Dr. Cheng earned his Ph.D. in Materials Science and Engineering from Monash University (2014) and a B.Eng. in Polymer Materials and Engineering from Wuhan University of Technology (2010). His research on membrane science and nanofluidics has been published in journals, including Nature, Science, Nature Nanotechnology, and Science Advances. Dr. Cheng is the recipient of multiple awards including the Membrane Science Award from the Membrane Society of Australasia, an ARC Future Fellowship, and the Australian Endeavour Research Fellowship. He was the Alumni Committee Chair for the MIT Postdoctoral Association (2018–2019) and MIT Communication Lab Fellow (2019). Dr. Cheng’s research and teaching focuses on transport phenomena, fluid mechanics, membrane science, and nanopore technology, with an emphasis on addressing critical challenges in resource and energy security.
Abstract:
Achieving net zero global transition requires the chemical industry to decarbonize, which in turn demands fundamental innovations in the engineering of momentum, mass, charge, and energy transfer with unparalleled efficiency and precision at the molecular level. Among many emerging clean technologies, precise control of ionic and molecular transport is oftentimes the limiting steps, preventing optimal performance in for example, membrane separations, batteries, and catalysts. However, due to the presence of competing forces, intricate structural and chemical interactions in nanosystems, unpredictable transport behaviors emerge, posing significant challenges in engineering nanofluids with molecular-level accuracy. In this talk, I will discuss advances in our understanding of precise engineering of nanofluids using monolayer nanoporous graphene membranes: (i) proposing a pathway for the scalable fabrication of angstrom-sized, tunable, atomically thin nanopores, (ii) developing combined experimental and theoretical approaches to study novel transport physics under nanoconfinement, and (iii) exploring fast and selective molecular transport as a function of structural and chemical interactions. I will first present our efforts in exploring liquid permeation through atomically thin nanopores, where the transport becomes sub-continuum and dependent on molecular geometry as pore size approaches the liquid’s smallest molecular cross-section. Then, I will discuss a recently developed method that leverages a cascaded compression approach to narrow the size distribution of nanopores created on a monolayer graphene lattice, resulting in a left-skewed distribution with ultrasmall tail deviation, while increasing the density of nanopores with each compression cycle. I conclude the talk by illustrating how engineering nanofluids can translate into new engineering solutions to address challenges in sustainable energy and manufacturing, specifically in chemical separations and electrochemical technologies.