Seminar 23rd March 2012 4 p.m. Building 27, Lecture room 2001
The Effect of Charge on Boundary Layer Lubrication
Professor Dominic Tildesley
VP Discover Platforms Unilever U.K. Central Resources Limited
- AMBER, Biomathematics, Biomechanics, C, C#, CASTEP, Complex Systems, COMSOL, CVS, Fortran, GPU, Gromacs, HECToR, HPCx, Lattice Field Theory, Maple, Materials, Mathematica, Molecular Dynamics, Molecular Mechanics, Monte Carlo, Multi-physics, Multi-scale, Multigrid solvers, Nanoscale Assemblies, NWCHEM, Optimisation, Photonics, Povray, Quantum Chemistry, Quantum Dynamics, Semiconductors, SVN, VMD, Windows
- Chris-Kriton Skylaris
Dissipative particle dynamics simulations are performed on two interacting polyelectrolyte brushes in an athermal solvent. The standard DPD model is modified by the addition of the electrostatic interactions and by the use of bond repulsion to model chain entanglement. For adsorbed polyelectrolyte monolayers the effect of salt concentration on layer thickness is observed and the results compared with the predictions of scaling theory.
The structural properties of neutral and polyelectrolyte brushes under compression are calculated at fixed solvent chemical potential. The highly charged brushes can support a larger load compared to neutral brushes at the same layer separation. A direct calculation of the friction from the stress tensor for two sliding layers shows that the friction coefficient between the charged polyelectrolyte layers is significantly lower than that of neutral polymer brushes and these results are compared with the experimental studies from the surface forces apparatus.