The Complexities of Bench-Top Fabrication of Hierarchically Structured Materials
Professor Jose Moran-Mirabal
Department of Chemistry and Chemical Biology
Wednesday, November 21, 2012
C2-361 (Reading Room)
Abstract: The fabrication of hierarchical materials − with features from the millimeter to the nanometer scale − is crucial to applications in diverse areas including biosensing, energy storage, photovoltaics, and tissue engineering. In the past, hierarchically structured materials have been produced using a combination of top-down and bottom-up fabrication approaches. A remaining challenge, however, is the simple fabrication of such materials using methods that allow the quick and inexpensive prototyping of functional devices. To address this challenge, my research group has developed a facile bench top method to create structured surfaces with features spanning the millimeter to nanometer scale. Our approach combines top-down, millimeter scale patterning through polymer stencils and thin film deposition; stress-driven thin film microscale structuring through shrinkable polymer substrates; and nanoscale structuring through electrodeposition of conductive materials. In this presentation, I will show how through the combination of these bench top methods, we have been able to produce hierarchically structured gold electrodes with features in three distinct length scales: 40 μm − 1 mm, 50 nm − 10 μm, and 20 nm − 2 μm. Electrodes fabricated in this fashion display excellent conductive and electrochemical properties, and can be successfully used to monitor charge transfer and reduction/oxidation reactions. Furthermore, the hierarchically structured electrodes fabricated exhibit electroactive surface area enhancements in excess of a thousand fold when compared to flat electrodes, which makes them attractive for biosensing applications. Our current research is exploring the use of the developed bench top fabrication approaches for the production of structured surfaces out of a wide variety of other materials.