|
While working at Pfizer Institute, I studied powder compaction using
the Descrete Element Method (DEM) to complement processing modelling on a Finite
Element Method (FEM) level done by my collaborators. The focus was on the relationship between the microscopic
characteristics (i.e. friction and restitution coefficients, Young's modulus)
of individual powder grains and the mechanical properties of the powder bed as a whole (i.e. the FEM parameters).
I have investigated the applicability of the Hertz-Kawabara-Kono model in DEM simulations of pharmaceutical
recipients and the benefits of simulating crushable grains as agglomerates of bonded spheres.
|
|
|
From April 2005 to March 2008, I studied polymer
adsorption using coarse-grained models in order to apply them to biologically relevant
systems such as those involved in biomineralisation. This work was within the inter-university
consortium 'Modelling
of the Biological Interface with Materials' and involved collaborations with researchers from
Sheffield, Warwick and UCL who performed DFT and atomic scale simulations. The
figure on the left demonstrates an off-lattice mesoscale model of a polysaccharide,
in which each glucosidic ring is coarse-grained as a single segment.
Generic mechanisms responsible
for the structure of polymer-nanoparticle mixtures and adsorption of macromolecules on surfaces
were studied together with several specific examples of selective adsorption of organic molecules
by inorganic crystals.
|
|
I also worked on the development of computationally efficient lattice based
methods to allow us to study polymer adsorption in different environments, e.g. near
a flat substrate or a nanotube, or in a suspension of nanoparticles.
We modeled a polymer chain as a self-avoiding walk on an FCC lattice and studied its
properties using Monte Carlo method with adaptive Wang-Landau sampling technique.
This method is very good for bulding phase diagrams as it predicts system's properties within
a wide temperature range in a single computer simulation.
|
|
|
From March 2003 to March 2005, I worked as a PostDoc at the Max
Plank Institute for Polymer Research in Mainz working
in Christian Holm's group.
My research project involved the development of theoretical and
simulation tools to model solutions of stiff-chain polyelectrolytes. Using a novel
cell model method we demonstrated that the inter-chain correlations make a very small
contribution to osmotic pressure in these systems and calculated 8(!) other contributions
to improve on the standard Poisson-Boltzmann treatment.
I also demonstrated that Local Density Approximations (LDAs) are not appropriate to
describe the excluded volume effect on the structure of the charged double layer.
Non-local approaches like Tarazona's functional should be used instead.
|
| I did my PhD at the Materials Research Institute at Sheffield Hallam University, with Doug Cleaver and Chris Care. The project entitled "Computer simulation of rod-sphere mixtures" involved the development of models to simulate bulk mixtures of liquid crystal and non-mesogenic substances. The internal structure of Gay-Berne and Lennard-Jones mixtures was studied at different densities, temperatures and parameters of intermolecular interaction. These structures then were subjected to an external applied field or alternatively their symmetry was broken by the presence of a colloidal particle. |
|
