报告摘要: Capillary forces play a significant role in number of practical applications related to microfluidic devices for detection of biomolecules, mixing of analytes and transport of fluid. Through first principle analysis, we have demonstrated that different regimes for capillary flow exist, both for horizontal and vertical capillaries. We have further performed in-depth studies to understand the role of the electric double layer in fluid transport in narrow confinements.

In parallel, wetting characteristics of a given sub­strate is of paramount importance in material science to characterize hydrophilic/ hydrophobic nature of the synthesized materials. We have developed a new method which allows us to characterize (measure contact angle) any substrate (superhydrophobic/ superoleophobic) using needle-free drop deposition technique, where the characterizing substrate can be kept either in air or submerged within a given liquid. We have also derived a new lubrication equation to characterize the coalescence behavior of two drops on under-liquid substrates. Using this technique of drop deposition, under-water superoleophobicity of glass surfaces and fish scales are characterized. Finally, some new results will be shared on development towards self-healing superhydrophobic surfaces in air and oleophobic surfaces in under-water.

报告人简介: Sushanta Mitra is the Executive Director of the Waterloo Institute for Nanotechnology and a Professor in Mechanical and Mechatronics Engineering and cross-appointed to the Department of Physics & Astronomy at the University of Waterloo. Before joining UW, he was the Associate Vice-President Research and Kaneff Professor in Micro & Nanotechnology for Social Innovation at York University. His research interests are in the fundamental understanding of fluid transport in micro and nano-scale confinements with applications in energy, water, and bio-systems. For his contributions in engineering and sciences, he has been elected as the Fellow of the American Society of Mechanical Engineers (ASME), the Canadian Society for Mechanical Engineering (CSME), the Engineering Institute of Canada (EIC), the Canadian Academy for Engineering (CAE), the Indian National Academy of Engineering (INAE – Foreign Fellow), the Royal Society of Chemistry (RSC, UK), the American Physical Society (APS), and the American Association for the Advancement of Science (AAAS). He is also a Fellow of the National Institute for Nanotechnology (NINT) and the recipient of 2015 Engineering Excellence Medal from the Ontario Society of Professional Engineers.