Executive Summary : | The growth of crystals from solution is a widely used in chemical and pharmaceutical industries to obtain pure materials. One of the main challenges in designing a crystallization process is in controlling the crystal structure of the final product. It is well known that crystalline materials can have multiple structures called polymorphs. This is because there are many ways in which molecules can be arranged in a three-dimensional crystal packing. Each crystal structure of the polymorph represents a local minimum in the free energy landscape.
The selectivity towards a particular polymorph during crystallization depends on process conditions such as temperature, supersaturation, solvent composition, additives, etc. However, our understanding of the relationship between the process conditions and the structure of the polymorph that nucleates from a solution is far from satisfactory. One of the main reasons for this state of affairs is due to incomplete knowledge of the molecular mechanisms involved during the earliest stages of crystallization, i.e., crystal nucleation. In this project we propose to use molecular simulations to study the early stages of crystal nucleation. The simulations are expected to shed light into the molecular mechanisms involved during nucleation and polymorph selectivity due to the influence of the surrounding solvent. |