报告题目: Mechanical Characterization of Nanoporous Thin Films using Optics and Short Pulse Lasers
报告人: Prof.Junlan Wang
Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA
Nanoporous materials (materials with pore size below 100 nm) are of significant interest to the scientific due to the size scale of the pores they contain and the wide range of functionality they can provide. Thin films and coatings containing nanometer sized pores have potential applications in many technology sectors such as antireflection optical coatings, low-dielectric-constant interlayer materials for interconnects in semiconductors, nanoscopic chemical reactors for catalysis, sensors, reactors, and many others. While increased levels of porosity are beneficial for achieving the desired functionality, high levels of porosity deteriorate the mechanical integrity of porous materials. To achieve both the functionality and the mechanical integrity of nanoporous thin films requires exact understanding of both microstructural and mechanical properties of these materails. One critical step in achieving this goal is to develop highly sensitive and reliable metrologies that can accurately quantify these properties. While the metrology for characterizing microstructural properties is relatively more mature, significant challenges exist in the mechanical characterization due to limitations of traditional experimental techniques. In this talk, Prof. Wang will discuss several optics and short-pulse-laser based techniques for characterizing the mechanical and interfacial properties of nanoporous thin films such as a laser-induced surface acoustic wave technique for mechanical property and laser-induced thin film spallation for interface adhesion. Due to their unique ordered crystalline porous structure and their dominating role in the nanoporous materials market, nanoporous zeolite thin films – a class of crystalline oxides containing silicon, aluminum and oxygen with intrinsic pores between 0.3-2 nm - will be chosen as the model system for discussion. The knowledge obtained and the metrology tools established are applicable to many other types of ordered and non-ordered nanoporous thin film materials.
Junlan Wang received her B.S. (1994) and M.S. (1997) degrees in Mechanics and Mechanical Engineering from the University of Science and Technology of China, and Ph.D. (2002) in Theoretical and Applied Mechanics from the University of Illinois at Urbana-Champaign. After spending one year as a PostDoc at Brown University, she joined the Department of Mechanical Engineering at the University of California, Riverside in 2003 where she was promoted to Associate Professor with tenure in 2008. Prof. Wang and her research group moved to the Department of Mechanical Engineering at the University of Washington, Seattle in December 2008. Prof. Wang is a recipient of the US NSF CAREER Award, the American Society for Engineering Education (ASEE) Beer and Johnston Outstanding New Mechanics Educator Award, the Bourns College of Engineering Teaching Excellence Award, and the Society of Experimental Mechanics (SEM) Hetenyi Award, etc. Prof. Wang is active in several professional societies such as American Society of Mechanical Engineers （ASME), SEM and ASEE including chairing the ASME Experimental Mechanics technical committee and Multifunctional Materials technical committee, and secretary for the SEM research committee. She is currently the Program Chair on the ASME Materials Division Executive Committee and will be the Conference Chair for 2015 ASME Mechanics and Materials summer conference (happens every four years)