Electrical Properties of Controlled, Longitudinal Wrinkles on Graphene Produced Via Bacterial-Scaffold Shrinkage

Wednesday, 27 May 2015: 16:00
Lake Ontario (Hilton Chicago)
S. Deng (University of Illinois at Chicago), T. S. Sreeprasad (Rice University), and V. Berry (University of Illinois at Chicago)
Wrinkles directly influence the electronic structure of graphene and thus its optical and chemical properties due to local p-orbital stretching, dipolar doping, and/or carrier puddling. Here, we show that bacteria’s ambiphilic cellwall chemistry (and texture), high surface energy, and transportable aqueous content with shrinkable microstructure makes them great scaffolds to induce controlled and confined wrinkles on interfaced graphene sheets. The relaxation of pre-stretched bacterial cell results in graphene wrinkles to orient in the longitudinal direction to the strepto-bacillus cereus cells with a texture aspect-ratio of 0.125. The wrinkle-wavelength is independent of the size of bacteria and the calculated wrinkle-wavelength of 32.5 nm is consistent with the observed wavelength of 32.4 nm – 34.3 nm. Under vacuum, bacterium covered with graphene dehydrates and shrinks; however, does not rehydrate at atmospheric pressure (like uncovered bacteria). This talk will (a) demonstrate directed electrophoresis of bacterial cells between electrodes for position-controlled 2D-wrinkle placement, and (b) discuss the electron density distribution and transport properties through wrinkled graphene. These graphenic bio-interfaced wrinkles can lead to novel nano/bio microelectromechanical systems with applications in electrical cell actuation, dehydration, sensing, restraining, retention, electro-microfluidics, and controlled delivery.