Mapping and controlling nucleation

The nucleation of a new phase from solution, such as the nucleation of crystals, is of immense importance to both industry and fundamental science. Industrial crystallisation has changed little in the past 350 years and suffers from an embarrassing lack of control with sometimes unexpected and severe financial consequences. Unfortunately, the theoretical understanding of crystal nucleation has not improved much since the work of Ostwald and Gibbs a century ago. Exceptions are the work by Cölfen on non-classical nucleation theories and that of Frenkel, on the role of critical density fluctuations in crystallisation. However, these new ideas are often applied within chemical engineering without a real understanding of the applicability of the underlying chemical physics.

Here it is proposed to map and control the early stages of nucleation in liquids. Nucleation will be treated in its most general form, that is, liquid-gas, liquid-liquid, and liquid-solid, while taking into consideration the possible presence of liquid-liquid critical points. Driving these systems very far from equilibrium, will allow us to create meta- and unstable states that will give rise to nucleation and spinodal decomposition. The subsequent highly non-equilibrium processes will be mapped using transmitted-light and Raman microscopy and, in particular, fluorescence microscopy using a range of environmentally sensitive fluorophores.

We propose to develop a novel instrument that will change the study of crystal nucleation and will make the first steps towards control over the polymorph that crystallises. It involves laser-induced nucleation using powerful picosecond and femtosecond lasers, and programmable diffractive optics, resulting in a massively parallel nucleation set-up. The resultant nucleation events will be followed in real-time using the mapping techniques developed previously. This breakthrough will allow us to carry out very large numbers of experiments and collect meaningful statistics for the first time. The massively parallel nucleation instrument will be used to carry out a number of nucleation-control experiments ranging from the relatively straightforward nucleation of liquid-crystalline phases or bubbles, to the induction of chirality in nucleation using "massively parallel optical stirrer beans" employing the spin and orbital angular momentum of light.

The impact of the proposed research will be discussed in four main areas: economy, knowledge, people, and society.

Economy

The proposal under consideration concerns the development of a new instrument and associated suitable liquids and solutions. It will lead to new fundamental insights into crystal nucleation and polymorph selection that will be applicable to industrial processes such as the production of drugs, pigments, etc. The development of massively parallel nucleation techniques using diffractive optics (programmable or static) may well lead to practical formulation methods and fits well with the EPSRC Manufacturing the Future theme. Through a visiting professorship in the Department of Chemical and Process Engineering at Strathclyde, contacts will be made with the chemical engineering community. Through the EPSRC Centre for Innovative Manufacturing in Continuous Manufacturing and Crystallisation (CMAC) funded by EPSRC, SFC, and industry, contact will be made with a user group of potential investors and industrialists. The University of Glasgow is a co-founding partner of Easy Access Innovation to promote new ways of sharing intellectual property. Finally, we are keen to share research equipment with the strategic aim to collaborate across traditional scientific boundaries, to develop new research strands, and to explore routes to impact.

Knowledge

The knowledge generated by the proposed work will be communicated through standard routes: papers, conferences, etc. The applicants have a good track record of getting results published in high impact factor journals. Other channels of knowledge transfer include the organisation of conferences such as the International Workshop on Ultrafast Chemical Physics (UCP) in Glasgow, sub-conferences at SPIE Photonics West and the International Conference on Time-Resolved Vibrational Spectroscopy (TRVS) to be organised by the PI and others in 2017 in the UK.

People

The research proposal under consideration here is people centred and career development of the team members a key aim. Key roles will be played by the ultrafast chemical physics collaboration between the PI and Hunt (UCP, http://www.ultrachemphys.org/) and the Biomolecular spectroscopy & dynamics Cluster (BioC, http://www.chem.gla.ac.uk/bioc/), which involves a group of researchers from Glasgow and Strathclyde Universities that specialise in biomolecular spectroscopy and in particular in dynamical processes. The PI has a history of successfully mentoring undergraduate and postgraduate students and postdocs. It is hoped that this good track record can be continued through the appropriate mentoring of RAs and PGRSs, for example, through the University of Glasgow's Researcher Development Framework.

Society

It will be attempted to communicate a flavour of the research enterprise and its results to the public. There are good reasons to believe that this might attract interest as YouTube is now featuring an increasing number of well-watched chemical science videos. The plan for the future in this area is to explore video as a medium for dissemination. These ideas are already being implemented and the group has a YouTube channel featuring our first few videos.