Aug 9, 2011
Quantifying dissipative interactions at the nanoscale
Reporting their results in the journal Nanotechnology, researchers have modeled dissipative interactions taking place at the nanoscale in terms of hysteresis and viscosity and as a combination of long-range non-contact and short-range contact processes. The scientists use concepts from dynamic atomic force microscopy to describe the physical phenomenon.
Their study focuses on the degree or level of localization in nanoscale dissipative interactions. This is typically ignored in the literature by either assuming that the dissipation occurs at a given point between the colliding bodies or by giving rough estimations of the area over which the energy is dissipated.
Figure of merit
The group, which includes scientists from institutes in the UAE, Spain, the UK and the US, calculates the effective area of interaction for each of the elementary dissipative processes. It then uses a figure of merit defined as M to quantify both the density of the energy dissipated and the level of localization of each dissipative interaction. Each process is shown to present a different pattern in M with decreasing separation between the colliding bodies from tens of nanometers to angstroms.
The work is theoretical, but uses parameters that can be readily measured with an atomic force microscope.
Predicting gas viscosity
The method could be used to predict the viscosity of different gases in nanometric confined volumes, and the team is currently exploring this idea.
More information can be found in the journal Nanotechnology.
About the author
Matteo Chiesa is based at the Masdar Institute of Science & Technology, UAE.