IEEE Electron Device Invited Talk by Dr. Sami Khan, Simon Fraser University - Robust Hydrophobic Surfaces for Enhancing Longevity of Sustainable Energy Systems
Abstract: Hydrophobic surfaces that are robust can have widespread applications in various industries including energy, hydropower, and transportation. Existing durable materials such as metals and ceramics are generally hydrophilic and require polymeric modifiers to render them hydrophobic, but these modifiers deteriorate in harsh environments. Therefore, robust hydrophobic surfaces have been difficult to realize and their widespread applicability has been limited. In this talk, the class of ceramics comprising the lanthanide series rare-earth oxides (REOs) will be discussed for their potential in enhancing the longevity of sustainable energy systems by repelling water. The unique electronic structure of the rare-earth metal atom inhibits hydrogen bonding with interfacial water molecules resulting in a hydrophobic hydration structure where the surface oxygen atoms are the only hydrogen bonding sites. Despite being inherently hydrophobic, the presence of excess surface oxygen on REOs can lead to increased hydrogen bonding and thereby reduce their hydrophobicity. Using X-ray Photoelectron Spectroscopy (XPS) and wetting measurements, surface stoichiometry and surface relaxations have been shown to impact wetting properties of REOs. Specifically, freshly sputtered ceria is shown to be hydrophilic due to excess surface oxygen (shown to have an O/Ce ratio of ~3), which when relaxed in a clean, ultra-high vacuum environment isolated from airborne hydrocarbons reaches close to stoichiometric O/Ce ratio (~2.2) and becomes hydrophobic. We also demonstrate that thin-film coatings (~300 nm) of hydrophobic REOs show sustained dropwise condensation behaviour for over 100 hours at accelerated saturated steam conditions without compromising structural integrity or hydrophobicity, and produce a tenfold enhancement in the heat transfer co-efficient (103 ± 5 kW/m2K) compared to conventional filmwise condensation (usually <10 kW/m2K). We will discuss applications of such hydrophobic surfaces in electronic devices and discuss embodiments with self-healing lubricant-infused surfaces that can provide corrosion protection in sustainable energy systems.
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- Burnaby, British Columbia
- Canada V5A 1S6
Speakers
Dr. Sami Khan of Simon Fraser University, School of Sustainable Energy Engineering
Robust Hydrophobic Surfaces for Enhancing Longevity of Sustainable Energy Systems
Biography:
Speaker biography: Dr. Sami Khan is an Assistant Professor in the School of Sustainable Energy Engineering at SFU. He obtained his Ph.D. in Mechanical Engineering from MIT in 2020. At SFU, Dr. Khan leads the Engineered Interfaces for Sustainable Energy (EISEn) group, which aims to improve the performance and longevity of sustainable energy systems by fundamentally understanding and tuning electro-chemo-physical interactions at interfaces, with a particular focus on enhancing CO2 capture and conversion processes. Dr. Khan is an expert in coatings that reduce fouling, corrosion and hydrogen ingress especially in harsh environments, with a US patent that was recently granted and licensed. He has previously worked in the rare-earth mining industry in Canada and was a Science and Technology Advisor at Natural Resources Canada recently. He is the recipient of many awards including the Marcel Pourbaix Award for Best Poster in Corrosion Science (received at the NACE international CORROSION conference in 2019), the NSERC PGS-D Scholarship (held 2016-2019), and the International Hydropower Association’s Young Researcher of the Year Award (2015). He serves as a Review Editor for Flexible Electronics, a specialty section of Frontiers in Electronics.
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Address:5118 - 10285 University Drive, , Surrey, British Columbia, Canada, V3T 0N1