Event Scheduled for Oct 23, 2017
Event: MSE PhD Proposal Defense - Keith J. Dusoe
Time: 11:00 am
Details of Event:
PhD Proposal Defense
Presenter: Keith J. Dusoe
Major Advisor: Dr. Seok-Woo Lee
Associate Advisors: Dr. George A. Rossetti, Jr., Dr. Avinash M. Dongare
Date: Monday, October 23, 2017
Time: 11:00 am
Title: Engineering Ultra-high Modulus of Resilience Materials by Metal-Oxide Sequential Infiltration into Negative Photoresist Nanostructures
Abstract: Modulus of resilience, the measure of a material’s ability to store and release elastic strain energy, is critical for realizing advanced mechanical actuation technologies in micro/nanoelectromechanical systems. In general, engineering the modulus of resilience in a given material system is not straightforward as it requires asymmetrical increases of yield strength and Young’s modulus against their mutual scaling behavior. This task becomes especially challenging once the material of interest approaches nanometer scale lengths. Sequential infiltration synthesis (SIS) is a novel vapor-phase nanocomposite technique that can greatly improve the strength and elastic energy storage/release capacity of polymeric materials at the nanoscale. To date, this work has demonstrated organic-inorganic hybrid composite nanopillars which achieve one of the highest modulus of resilience per density, by utilizing vapor-phase aluminum oxide (AlOx¬) infiltration in lithographically patterned negative photoresist SU-8.
In-situ nanomechanical measurements of hybrid nanopillars reveal a metal-like high yield strength (~500 MPa) with an unusually low, foam-like Young’s modulus (~7 GPa), a unique pairing of mechanical properties which yields ultra-high modulus of resilience, reaching up to ~24 MJ/m^3 as well as exceptional modulus of resilience per density of ~13.4 kJ/kg, surpassing those of most engineering materials. It is proposed here that fundamental investigations which synergistically combines MEMS/NEMS-compatible lithographic polymer patterning, novel vapor-phase material hybridization (SIS), advanced structural/chemical characterization and in-situ nanomechanical characterization are to be carried out to understand the molecular scale infiltration process, formation of unconventional hybrid nanostructures, and origins of unusual nanomechanical properties.
Target Audience: Not Available
Sponsored By: Materials Science and Engineering Department
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