PRACE: Understanding and Predicting the Properties of Clay-Polymer Nanocomposites using Petascale Computing

Project leader: Peter Coveney, University College of London Department of Chemistry, United Kingdom
Collaborators: Dr Derek Groen, University College of London, United Kingdom / Dr James Suter University College of London, United Kingdom / Mr Jacob Swadling University College of London, United Kingdom

Abstract

Nanocomposites fall within the realm of the emergent area known as nanotechnology, where materials are designed and built at the atomic level. They consist of two-dimensional mineral layers separated by polymeric or organic material and possess novel mechanical, barrier, thermal and biodegradable properties. Nanotechnology is therefore an area which is of great academic, industrial, health and public interest. Various materials using layered nanoparticles have already been proposed for commercial applications in automotive, packaging, coating and pigment, electrical materials, and biomedical fields. Understanding how the microscopic structure of layered nanomaterials determines their (improved) macroscopic properties requires an approach that tackles a wide range of length scales, from nanometers to microns, each of which is vital for the mechanism of enhancement. Therefore, we require nanomaterials simulations which operate on multiple length scales, and encompass this complete structural hierarchy. With the knowledge of how this structural hierarchy functions will we be able to design novel layered mineral systems with properties tailored to their application. To sample the smallest modes of action we require detail on the molecular scale. We are therefore performing very large scale molecular simulations and using efficient sampling techniques to increase the length and timescales accessible with molecular simulation far beyond what is currently possible, to the micrometre and millisecond range, enough to fully sample all the modes of action of the layered nanomaterial. We plan to use our simulations to answer two important challenges in layered nanomaterials: First, we will evaluate the mechanism of polymer-nanocomposite formation and the effect it has on the overall material strength of the composite. We can only optimize the manufacturing process if we have a good understanding of the rheological properties and the mechanism of formation. This study will allow us to predict which products will create a homogenous nanocomposite with defined materials properties. Second, we will study the interaction between biological molecules and clay surfaces. These interactions are of great interest, as clay minerals are used in the development of new drug delivery systems, gene therapy and origins of life studies. The clay protects the drugs / biological molecules to reach the site of action and maintain a certain concentration during pharmaceutical treatment. For origins of life studies, one of the leading theories concerning the origin of life is the RNA world hypothesis, where RNA molecules carried out the tasks that DNA and proteins perform in contemporary cells. It is hypothesised that the occurrence of various steps towards the formation of a very complex molecule, such as RNA, must have required the presence of a protected confined environment, where RNA, or an RNA-like molecule, could originate and express its biological potential to self-replicate and evolve. In this project, we will be evaluating this hypothesis by understanding how primitive RNA adsorbed on clay-mineral surface may have been in the right conditions to undergo specific chemical reactions, triggering molecular evolution. This is also important in understanding how clay minerals provide a protective environment for biomolecules in gene-therapy. Such complex and challenging simulations can only be performed on today’s most powerful supercomputers, such the JUGENE BlueGene/P Tier-0 machine at FZJ.

Computer system: JUGENE, GAUSS/FZJ

Resource awarded: 40 500 000 core-hours