Abstract: Microfluidics has become an important research topic over the past over the past 15 years. Nearly all microfluidic devices to date consist of some type of fully-enclosed microfluidic channel. The concept of ‘free-surface’ microfluidics has been pioneered at UCSB during the past seven years, where at least one surface of the microchannel is exposed to the surrounding air. Surface tension is a dominating force at the micron scale, which can be used to control effectively fluid motion. There are a number of distinct advantages to the free surface microfluidic architecture. For example, the free surface provides a highly effective mechanism for capturing certain low-density vapor molecules. This mechanism is a key component (in combination with surface-enhanced Raman spectroscopy, i.e. SERS) of a novel explosives vapor detection platform, which is capable of sub part-per-billion sensitivity with high specificity. This platform is currently being commercialized for homeland security applications by SpectraFludics, Inc.
In another application through collaboration with the MacDonald group at UCSB, free-surface microfluidics is combined with titanium-based MEMS to produce flat heat pipes. Titanium-based MEMS has unique fabrication advantages in that it can be (1) micromachined in a cleanroom, (2) macro-machined, and (3) laser welded. Numerical simulations are used to optimize the microchannel design to enhance heat transport in flat heat pipes. Experiments show that these types of flat heat pipes are light weight, robust under harsh conditions, and can perform with an effective conductivity approaching ~10,000 W/(m K).
Bio: Dr. Meinhart is a professor of Mechanical Engineering at the University of California – Santa Barbara, and is a co-founder of SpectraFluidics & Pi-MEMS. He completed his PhD and Postdoctoral work at the University of Illinois in June of 1995. At the University of Illinois, his research involved the investigation of turbulent flows. Since coming to UCSB in 1996, his research has focused on developing microfluidic devices and exploring their fundamental transport mechanisms. Dr. Meinhart is a fellow of the American Physics Society.
Prof. Meinhart’s group pioneered the concept of free-surface microfluidics. In collaboration with Prof. Martin Moskovits’ group in chemistry at UCSB, and their respective students, they have developed a novel technique for measuring gas-phase chemicals with very high sensitivity. This work was featured in The Wall Street Jounal, and the Feb. 2013 issue of Mechanical Engineering Magazine. In collaboration with Prof. Noel MacDonald’s group and students, they applied free-surface microfluidics to develop novel titanium-based heat pipes