Thursday, March 29, 2012
106 Spalding Lab, Hartley Memorial Seminar Room
Chemical Engineering Seminar
In Wonderland of polymer pillar arrays
Shu Yang, Associate Professor, Materials Science and Engineering, University of Pennsylvania
High-aspect-ratio pillar arrays present many unique features, including large surface area, a true surface topography that is well-separated from the underlying substrate, and large mechanical compliance. In nature, these features have resulted in evolutionary functions, including reversible dry adhesion of gecko foot hairs, superhydrophobic surface of lotus leaves, and enhanced local interactions with cell membrane structures such as microvilli and filopodia.
In my talk, I will present our recent work on fabrication of polymer micropillar arrays, study of their stabilities against adhesive and capillary forces in dry and wet states, respectively. By taking advantage of the mechanical compliance and instabilities, we investigate potential applications in cell differentiation, tunable dry adhesion, and switching of optical properties,as well as their integration as sensors in design of energy efficient buildings.
In a separate vein, we utilize the polymer pillars as templates to direct epitaxial assembly of liquid crystal molecules and phyllotaic assembly of nanoparticles.