Thursday, July 14th 2022, 11 a.m., Seminar room, U5 Building – via Roberto Cozzi 55, Milano.
Lecturer: prof. Mingdong Dong ,The Interdisciplinary Nanoscience Center (iNANO) Aarhus University, Denmark
Title: Two-Dimensional Materials Confined Water
Abstract: The interface between water and other materials under ambient conditions are of fundamental importance due to their relevance in daily life and a broad range of scientific research. The structural and dynamic properties of water at an interface have been proven to be a significant difference from those of bulk water. However, the exact nature of these interfacial water adlayers at ambient conditions is still under debate. Recent scanning probe microscopy (SPM) experiments, where two-dimensional (2D) materials such as ultrathin coatings are utilized to assist the visualization of interfacial water adlayers, have made remarkable progress on interfacial water and started to clarify some of these fundamental scientific questions.
In this talk, we review the recently conducted research exploring the properties of confined water between 2D materials and various surfaces under ambient conditions. We focus on the studies of water adlayer growth at both hydrophilic and hydrophobic substrates in the presence of 2D coating materials. Ice-like water adlayers confined between hydrophobic graphene and hydrophilic substrates can be directly observed in detail by SPM. It was found that the packing structure of the water adlayer was determined by the hydrophilic substrates, while the orientation of intercalation water domains was directed by the graphene coating. In contrast to hydrophilic substrates, liquid-like nanodroplets confined between hydrophobic graphene and hydrophobic substrates appear close to stepping edges and atomic-scale surface defects, indicating that atomic-scale surface defects play significant roles in determining the adsorption of water on hydrophobic substrates. In addition, we also review the phenomena of confined water between 2D hydrophilic surfaces and the hydrophilic substrate. Finally, we further discuss researchers taking advantage of 2D coatings to stabilize confined water nanodroplets to manipulate nanofluidics by applying an external force by using novel SPM techniques. These new findings potentially can be utilized to understand the boundary condition for water structures and dynamic behaviors at interfaces, and the aqueous interfacial chemistry
Biography: Dr. Mingdong Dong is currently working as a Full Professor and a group leader at the Bio-SPM group at Aarhus University Denmark. He obtained his Bachelor's, Master's, and Ph.D. degrees from China, Sweden, and Denmark respectively. After obtaining his Ph.D. degree from Aarhus University, Denmark (2006), he continued with a Postdoctoral Research Associate Position at Harvard University, USA. Dr. Dong has published more than 300 papers (More than 15000 citations) in top international peer-reviewed journals such as Nature, Nature Nanotechnology, Nature Chemistry, Nature Communications, PNAS, Angewandte Chemie, Nano Letters, JACS, Small, ACS NANO, Advanced Materials, etc. Dr. Dong has been a member of ACS, MRS, Biophysical Society, and Fellow of the RSC (FRSC). Dr. Dong also serves as a board member or editor for international peer-reviewed journals, including Nature group scientific report, the Royal Society of Chemistry EES and RSC advances, American Institute of Physics AIP Advances, Computational and Structural Biotechnology Journal, etc. He also serves as grant reviewer panel for EU, USA, UK other different national research councils, and serve as a reviewer for major scientific journals.