In my current role as a Theme Lead in Computational Materials Design at the Leverhulme Research Centre, I am involved in several research projects that use computational chemistry to study materials properties. By understanding how materials function we can design new materials with higher efficiency and materials that simultaneously have several desired properties. To achieve this we develop predictive computational tools that combine existing chemical knowledge with computational chemistry and computer science methods.
Metal-organic frameworks (Liverpool, UK)
Metal-organic frameworks are hybrid materials in which metal ions are connected by small organic molecules (linkers) to make a regular 3D structure which resembles a molecular sieve. Depending on the linker/metal combination these structures can either be rigid or can close their pores in responce to the experimental conditions. By modelling these materials on the computer and applying machine learning techniques, we advance the understanding of the mechanisms responsible for this behaviour and guide the experimental work by predicting most promising linker/metal combinations.
Biodegradable polymers (Cambridge, UK)
Biodegradable polymers are becoming increasingly popular as scaffolding/matrix for tissue engineering and in drug delivery applications. These materials degrade in the presence of water into non-toxic components naturally present in the human body. In collaboration with experimentalists I was working on identifying routes to control the rate of the degradation and its effect on the mechanical properties of the scaffolding.
Pharmaceutical powders (Cambridge, UK)
Tablets are made by compacting pharmaceutical powders under a high-pressure punch. In this project, I developed new theoretical models which describe what happens to the powder while it is being compacted. In particular, I studied how the parameters of the individual powder grains relevant to their breakage and rearrangement under pressure translate into bulk properties of the powder. The main aim was to optimize the compaction process so as to prevent temperature-sensitive drugs from overheating and to produce more uniform crack-free tablets with longer shelf lives.
This work involved collaboration with chemists and computational scientists from the Pfizer Institute and a lot of programming to modify the third-party software package (DL_POLY).
Biomimetic materials (Cambridge, UK)
I started my work in Cambridge as part of the inter-university 'Modelling of the Biological Interface with Materials' which involved over 20 researchers from Sheffield, UCL, Warwick and Cambridge. The common point of interest was the interface between hard inorganic crystals and soft organic materials. Why does lime scale from the kettle look nothing like a sea shell? It appears that the presence of certain sugar-like molecules can affect crystal growth in a solution resulting in the beautiful structures seen in corals, sea shells and planktons.
As a part of this project, I developed a simulation package for polymer lattice modelling and was also responsible for coordinating a consortium subproject on mesoscale modelling. In collaboration with three other members of the consortium, we
- identified surface recognition mechanisms for specific peptides and polysachharides
- predicted mechanical properties of polymer-nanotube composite materials
- developed a methodological approach to study such systems efficiently
Polyelectrolytes (Mainz, Germany)
When some chemicals (like DNA) are put in water, their charged groups of atoms can detach from the backbone and float around it held by the electrostatic forces. I developed two different theories to compute the spatial distribution of these groups and hence predict their physical properties. This work resulted in three publications and helped to explain what effects contribute to osmotic pressure in polyelectrolyte solutions.
Alongside other polyelectrolyte group members, I also contributed to the Extensible Simulation Package for Research on Soft matter or ESPResSo.
Liquid crystals (Sheffield, UK)
In a liquid crystal, rod-like molecules spontaneously align in the same direction, similar to matches in a match box. In my PhD I studied how this order can be altered by the addition of small spherical molecules with specified attractive interactions. These rod-sphere mixtures were found to produce a variety of self-assembled structures, whose properties can be changed by applying an electric field.
This work resulted in three publications, three follow-up PhD projects, an international collaborative research project and also attracted attention in both industrial and academic circles. The idea that additives in a liquid crystal tend to reside at defect points and can even change the type of this defect was recently employed to design a sensor for endotoxin.
