High aspect ratio, densely populated, pillar arrays for separations

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With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Michael Sepaniak at University of Tennessee, Knoxville and his group will tackle the challenges of creating pillar arrays for chemical separations (PACS) that function as miniaturized liquid phase separation systems. An original processing sequence for the fabrication of high aspect ratio pillars yields mechanically robust systems. Importantly, the characteristic morphologies in the implemented highly ordered pillar arrays are scalable to nanometer dimensions. Thus the fluidic structures, operated in enclosed pressure-driven or open capillary action-driven modes, offer the potential for substantial improvements in separation efficiency and permeability over traditional packed and monolithic columns, as well as traditional thin layer chromatography plates. Porosity and nanoscale morphology in conventional separation systems is generally random and, therefore, morphological heterogeneity and related mass transfer issues play a significant role in band broadening. Conversely, PACS provides an alternative approach to separation media with precisely controlled nano- and micro-scale architectures. New insights into the retention mechanisms in nanoscale fluidic systems are expected. Moreover, advanced lithographic techniques will be used to create for the first time uniform pillar structures suitable for high performance open format, 2-D spatial separations. In addition to the scientific objectives of this proposal, an underpinning goal is to introduce young researchers to cross-disciplinary science and technology ranging from microfabrication and nanotechnology, studies of surface properties, and the development of new instrumental approaches to separations, fluidics, and ultra low volume detection/imaging. Efforts to recruit minorities and disseminate research results will be leveraged by prior experience with programs such as our prior NSF programs and Sepaniak's collaboration with the University of Puerto Rico. Finally, an outreach educational component is included that involves summer research experiences for visitors which emphasizes bringing area high school teacher-student combinations to the UT campus.