Publications

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The synthesis of two new polyphenylene vinylene (PPV) precursor polymers which can be thermally induced to eliminate pentanol is presented. Pentanol has recently been discovered to be a very useful lubricant in MicroElectroMechanical Systems. The utilization of the elimination reaction of precursor polymers to PPV as a small molecule delivery platform has, to the best of our knowledge, not been previously reported. The elimination reactions were examined using thermal gravimetric analysis, gas chromatography, and UV-Vis spectroscopy. Using PPV precursors allows for (1) a high loading of lubricant (one molecule per monomeric unit), (2) a platform that requires relatively high temperatures (>145 °C) to eliminate the lubricant, and (3) a non-volatile, mechanically and chemically stable by-product of the elimination reaction (PPV). The "on-demand" delivery of a vapor-phase lubricant to MicroElectoMechanical Systems (MEMS) will allow for scheduled or as-needed lubrication of the moving components, improving the performance, reliability, and lifespan of the devices. A delivery system utilizing a newly designed microhotplate along with two new precursor poly(p-phenylene vinylene) polymers that thermally eliminate a pentanol lubricant is described. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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MicroElectroMechanical Systems (MEMS) have become commercially successful in a number of niche applications. However, commercial success has only been possible where design, operating conditions, and materials result in devices that are not very sensitive to tribological effects. The use of MEMS in defense and national security applications will typically involve more challenging environments, with higher reliability and more complex functionality than required of commercial applications. This in turn will necessitate solutions to the challenges that have plagued MEMS since their inception - namely, adhesion, friction and wear. Adhesion during fabrication and immediately post-release has largely been resolved using hydrophobic coatings, but these coatings are not mechanically durable and do not inhibit surface degradation during extended operation. Tribological challenges in MEMS and approaches to mitigate the effects of adhesion, friction and wear are discussed. A new concept for lubrication of silicon MEMS using gas phase species is introduced. This "vapor phase lubrication" process has resulted in remarkable operating life of devices that rely on mechanical contact. VPL is also an effective lubrication approach for materials other than silicon, where traditional lubrication approaches are not feasible. The current status and remaining challenges for maturation of VPL are highlighted. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

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