Advanced Nanomaterials Manufacturing: Fluid Flow Assisted Control of Nucleation and Self-Assembly Processes

Konstantinos has been working for 3 months on a mini-project, sponsored by the Strathclyde University funding mechanism called “Bridging the Gap”.

The £16k mini-project, headed by Monica Oliveira,  is called Advanced Nanomaterials Manufacturing: Fluid Flow Assisted Control of Nucleation and Self-Assembly Processes, and also involved experimental researchers from Strathclyde’s Chemical & Process Engineering Department. Its aim was to construct a fluidic platform with interchangeable geometries to generate and control different flow kinematics in order to analyse the effect of fluid dynamics on nucleation.

The numerical part of the work was computer simulations using and extending our existing molecular dynamics (MD) code in order to obtain deeper insight into the fundamental phenomena.

After the first meeting with the involved partners, we decided to develop a new Brownian Dynamics (BD) code using OpenFOAM. The main reason for this is the time and length scales involved in the experiments: MD would only be able to simulate a nanoscale system with around 10 nano-particles and thousands of water molecules, or thousands of nano-particles in vacuum, for problem times up to only a few microseconds, in the time available for the mini-project. Our new BD code enables us to simulate thousands of nano-particles, with sizes (R = 25 nm, simulation box length = 4 micrometres on 2 CPU cores) far exceeding what any MD code can achieve, and for timescales of the order of milliseconds. We also implicitly include the presence of water through the diffusion tensor.

If you want a copy of this code, please just email Konstantinos. The code has been successfully compared with results given in the book “Introduction to Practice of Molecular Simulation” (by Akira Satoh) for a Lennard-Jones fluid. Introducing a mixed potential leads to the nucleation of the nano-particles. This potential can also be used in MD simulations and can be easily altered. Konstantinos has been performing equilibrium simulations as well as other cases with a body force or a shear stress, and is currently investigating the effect of imposing a flow on the cluster distribution or the clustering rate. These results, along with the information about the flow, could be a guide for future experiments and the design of micro-devices.