Computational studies of phosphate clusters and bioglasses

• Main Author: Tang, E.
• Published: University College London (University of London) 2011
• Subjects: 540
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.565404

The aim of this PhD research project is to investigate the aqueous behaviours of phosphate species and the structure of bioactive phosphate glasses via computational modelling. Density functional theory has been employed as the core methodology throughout the project. The molecular structures of bioactive ternary phosphate-based glasses with compositions (P2O5)0.45(CaO)x(Na2O)0.55-x, where x = 0.30, 0.35 and 0.45, have been explored by a range of Car-Parrinello molecular simulations. Careful structure analysis has been carried out in order to provide an accurate description of the local structure and properties of these important materials for biomedical applications. This is followed by the Car–Parrinello molecular dynamics simulations of the first hydration shell structures. Extensive simulations provide new insights into hydrogen transfer and intermolecular and hydration properties of these important aqueous species. Apart from ab-initio molecular dynamics calculations, first principles density functional theory calculations with a cluster-continuum solvation model have been used to evaluate the relative energetic stabilities of various phosphate oligomers in an aqueous environment. As a result, an illustrative picture of different aspects of phosphate species related to the dissolution behaviour of bioactive phosphate glasses was built up from various angles, which will form a solid foundation for further computational studies of bioactive phosphate glasses in the future.