School of Physics, GeorgiaTech
837 State Street, Atlanta, GA 30332-0430 USA
Phone: +1 (404) 894 6580
Research Area: Liquid dynamics in nano-confined geometries and Nanolitography
This project will explore the dynamic properties of water solutions in nano-confined geometries. The understanding and the ability to manipulate fluids at the nanoscale is a matter of continuously growing scientific and technological interest. Fluid flow in nano confined geometries is relevant for biology, polymer science and geophysics. The applications range from gene sequencing to protein segregation, cell sorting, bio and chemical sensors, nanotribology and diffusion through porous media. Confined fluids exhibit unique structural, dynamical, electrokinetic, and mechanical properties that are different from those of the bulk. Surprising effects have been found when water is confined in nanogaps. For example, the room temperature electric field induced freezing of water and the extremely high viscosity of water close to a mica surface. Also the usual no-slip (zero-velocity) boundary condition is no longer valid when we describe fluid flow in confined geometries, leading to unexpected flow velocities in nanochannels.
The goal of this project is to understand the dynamic properties, namely viscosity, slippage and electrokinetic effects, of water solutions confined in gaps and/or channels with dimensions in the range from zero to twenty nanometers. The role of confinement, temperature, ion concentration, ion specificity, electric field, surface chemistry, and surface roughness, will be investigated. We plan to use state of the art atomic force microscopy and to develop a new, fast, simple and versatile thermo-chemical nanolitography technique for the fabrication of nanopatterned surfaces and nanochannels with sub-15 nm dimensions.
Research Area: NanoMechanics, Elasticity and Friction in Nano-Objects
The development of new materials with the size of a few nanometers has opened a new field of scientific and technological research. Nanomaterials such as carbon nanotubes, oxide nanobelts and semiconductor nanowires are promising building blocks in future integrated nanoelectronic and photonic circuits, nano-sensors, interconnects and electro-mechanical nanodevices. The goal is to develop faster and better communication systems and transports, as well as smarter and smaller nanodevices for biomedical applications. To reach these objectives it is crucial to have knowledge of and the ability to control the mechanical behavior of these nano-objects.
In general, the mechanical properties of the materials at the nanoscale are not well understood, for example it is still not clear what is the nanoscopic/atomic origin of the phenomenological friction laws of Leonardo da Vinci. The experimental challenge is to have an instrumentation that allows us to image and manipulate a nano-object, characterize its atomic structure and measure forces of few nanoNewtons. From the theoretical side, developing a theory of elasticity and friction at the nanoscale is an intriguing task that lies at the cross-over between the atomic level and the continuum.
In this project we plan to study the nanoscopic mechanical properties, namely elasticity and friction, of several kinds of nano-objects. Our strategy is to use state of the art Atomic Force Microscopes to image and perform force measurements, whereas the structural and chemical local characterization of the nano-objects will be achieved by means of transmission electron microscopy and tip-enhanced Raman spectroscopy. This project will be developed in close collaboration with several national and international labs for nano-objects deposition as well as for theoretical calculations on the mechanical properties of nano-objects