Structure of Interfaces and Nanoparticles
Dr. Donald R. Franceschetti
The performance of electrochemical sensors in biomedical applications depends crucially
on the characteristics of the space charge layers formed on both sides of the interface
with the sample as well as the transport and storage of charged and uncharged species
at the interface. The electrical, mechanical, and other properties of nanoparticle
composites likewise depend on the space charge layers near the surfaces of the component
nanoparticles, with the interesting possibility that bulk electroneutrality exists
nowhere inside the particles.
Our work is theoretical and computational. A theoretical baseline is provided by solutions
of the Nernst-Planck Poisson equation governed by boundary conditions describing interfacial
processes and possibly coupled to diffusion equations for neutral reactants or products.
This system is well explored in one dimension but must be treated numerically for
two- and three- dimensional geometries, coupled to elastic distortions, and corrected
for discreteness of charge effects. In additional to mathematical modeling of space
charge structures, we have capabilities for nonlinear least squares fitting and interpretation
for impedance measurements made on experimental systems.
For more information, please contact Dr. Donald Franceschetti at firstname.lastname@example.org, or 901.678.5257.
Nanoparticles in Polymer Blends
Dr. Mohamed Laradji
It has been suggested that nanoparticles may act as emulsifiers in immiscible polymer
blends, allowing the two components to blend at temperatures below the blend's critical
temperature. Through large-scale Dissipative Particle Dynamics (DPD) computer simulations,
we have seen that nanoscale particles -- particularly those which exhibit geometrical
anisotropy as in nanorods -- can greatly slow the phase separation dynamics in a binary
polymer blend, and may lead to a micro-phase separated state. These results are not
seen for spherically-shaped nanoparticles. We continue to investigate the effects
of the addition of nanoparticles to immiscible polymer blends through both theory
and numerical simulations (with methods including Molecular Dynamics, Dissipative
Particle Dynamics, and Langevin Dynamics). See also the department's research on polymers and polymer blends.
- 20 node, 3.06 GHz Pentium-4 Beowulf cluster.
- Access to a variety of medium to large scale computer clusters.
Below: A snapshot from a DPD simulation (containing approximately 2,000,000 particles) of
a binary immiscible polymer blend containing nanorods.
For more information, please contact Dr. Mohamed Laradji at email@example.com or visit his website.