| dc.description.abstract | Crystalline materials are found in a numerous variety of geometrical forms both in nature and when produced synthetically. As a result, pathways of crystal nucleation, growth and assembly into larger structures have evoked significant scientific interest for centuries, aiming at understanding how crystal forms emerge. Answering this question not only satisfies our intellectual curiosity but also paves the way for design and fabrication of advanced materials, where optical, mechanical and biological properties can be modulated via crystal shapes. In this context, the purpose of this work has been to investigate the morphology development of crystalline particles and determine the primary factors controlling their final shapes. The motivation for this study was founded on the continuing debate in explaining, in particular, the formation mechanisms of branched crystals and polycrystalline particles with nanosized subunits and nanoparticulate surface features by the two prevailing hypotheses, the classical and non-classical mechanisms of size enlargement. The classical crystallization theory defines crystal growth by monomeric addition of building units and explains morphology development as a function of the thermodynamic driving force, i.e., supersaturation, while the non-classical hypotheses attribute crystal growth to aggregation or assembly of nanoparticles and define effective parameters of growth related to colloidal stability and assembly mechanisms. In order to investigate the governing parameters for crystal growth and morphology development and explore the universality of the proposed mechanisms, the atomic systems of metallic gold and silver and the ionic system of vaterite, a calcium carbonate polymorph, were used. For all systems, the results of this work have demonstrated the strong correlation of particle morphology with the thermodynamic driving force for growth, which is elucidated within the framework of classical crystal growth theory. | en_US |
