Department of Physics

Physics Colloquium


DATE:           Friday, January 16, 2015
TIME:           12:20 pm - 1:35 pm
LOCATION:   301 Campbell Hall

"Adventures in Nanoscale Mechanics"

Professor Peter M. Hoffmann
Department of Physics & Astronomy
Wayne State University

Abstract

The mechanics of even simple systems, such as pure liquids, can exhibit surprising behavior at the nanoscale. Nanoconfined liquids are of great interest in biology, tribology, geology and nanoscience, but their mechanical and dynamical behavior is not well understood. In our lab, we have developed, built and used novel atomic force microscopy (AFM) techniques to measure the nanomechanics of liquids confined to nanoscale spaces.  We have discovered novel behavior, including a prominent dynamic transition from viscous to elastic behavior at extremely slow compression speeds, indicating relaxation times many orders of magnitude slower than molecular collision times. This behavior is likely due to molecules being forced to move collectively and is reminiscent of supercooled liquids close to the glass transition. I will also briefly discuss our research on single molecule measurements of ligand-protein interactions, where we are currently developing capabilities to perform measurement on live cells and to combine AFM with fluorescence microscopy.