Simulation of Non-uniform Polymer Fluids


Principal Investigator

Clifford Woodward

Chemistry,Australian Defence Force Academy,University of NSW


Adam Czezowski

School of Chemistry, Australian Defence Force Academy, University of NSW


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Many systems of natural and industrial
importance contain a mixture of large colloidal
particles and polymers. It is found that the polymer molecules can have a profound influence on the way that the colloidal particles interact. This study aims to develop theoretical methods to study the interaction between colloidal particles, as mediated by polymer molecules. We use Monte Carlo simulations in order to obtain the forces between planar surfaces, which confine a polymer solution. Our method incorporates a novel ensemble, which allows us to simulate under conditions appropriate to an open system, without using impractical particle exchanges. The results of this work will have significance across a broad spectrum of natural and technological phenomena.


What are the results to date and the future of this work?

A new simulation program, based on the semi-grand Isotension Ensemble has now been completed. This program allows us the possibility of explicitly simulating solvent particles, as well as polymer, at constant chemical potential. The advantage of this type of simulation is that effects due to solvent structure can now be modelled exclusively. As well, we can study the effects of good and bad solvents, by making the solvent and monomers either mutually attractive or repulsive. These factors should have a major influence on the surface forces.

The new ensemble described above also allows us the possibility of examining surface forces in fluids consisting of mixtures of large and small particles, for example, a colloidal solution. Recently there has been some interest in the interaction between surfaces in the presence of globular proteins.

What computational techniques are used?

Our research makes use of Monte Carlo simulation methods in order to generate particle configurations, consistent with an appropriate thermodynamic ensemble. The computer programs we use are written in FORTRAN 90.

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