Flow-Xl: A New UK Facility for Analysis of Crystallisation in Flow Systems

Crystalline materials are everywhere. They are abundant in nature (eg bones and seashells) and in the environment (eg. rocks and ice) and are found across a diverse selection of everyday products including pharmaceuticals, batteries and food.

Crystallisation can also be undesirable, such as in the formation of kidney stones or scale in a kettle. The ability to control crystallisation processes - to generate particles with specific sizes, shapes and structures, and to control where and when crystallisation occurs - therefore promises huge benefits to society. Here, we need to develop strategies to prevent crystallisation.

All of these goals can only be achieved by developing a robust understanding of the mechanisms that underlie crystal nucleation and growth. This project will create a new UK, and indeed world-first research facility - Flow-Xl - that can address this challenge.

Unique analytical capability

Flow-Xl will be located at the University of Leeds and will enable in situ, time-resolved characterisation of crystallisation processes in highly controlled environments. This will be achieved by coupling X-ray diffraction and Raman spectroscopy to a range of fully-integrated flow platforms. These analytical techniques will be used simultaneously to study crystallisation pathways from amorphous and poorly crystalline precursor materials, through crystalline intermediates, to the ultimate crystal products.

This combined capability is not currently available anywhere else in the world. Flow-Xl is also extremely timely, where it is only possible because top-of-the-range laboratory X-ray instruments are now so good that they can replace synchrotrons for many experiments. Parallel innovative data processing and analysis methods will be developed and provided for Flow-Xl users, building on our key breakthrough methodology. These will allow the maximum information to be obtained from Flow-Xl experiments.

The use of flow systems is also critical to our technique, and Flow-Xl will offer a number of contrasting flow platforms. The simplest of all is continuous flow, which mimics many industrial manufacturing processes. Many industrial crystallisation processes also take place in stirred vessels, and these environments will be studied by withdrawing solution from a batch reactor through a flow loop for analysis.

Finally, it will be possible to study crystallisation in segmented flow, where individual droplets provide highly reproducible reaction environments that are ideally suited to fundamental studies of crystallisation mechanisms.

Valuable expertise

Flow-Xl will also enable us to share our expertise in the manufacture of flow-cells for X-ray measurements with the entire UK research community. Flow-Xl will be operated as a multi-user facility that is open to all academic and industrial researchers across the UK, and will be supported by an experienced research officer. This will allow the equipment to be fully utilised for a wide range of projects spanning industrial processes through to developing fundamental understanding.

In addition to providing a cutting-edge, stand-alone research facility, Flow-Xl will also support Diamond Light Source and its users by providing an alternative or precursor to synchrotron time for many experiments. This frees-up precious beam-time for experiments that really need it, and enables researchers to conduct screening/ feasibility experiments prior to their beam-time.

The facility will support a range of existing projects including the formation of organic framework compounds, biomineralisation and bio-inspired crystallisation, fouling, materials discovery, production of single enantiomer crystals, polymorph selection and the development of artificial intelligence in modelling of crystallisation. By building a strong user community from academia and industry over the course of the project, we will ensure this powerful new facility finds application across a wide range of scientific programmes.