Crystallisation in the Real World: Delivering Control through Theory and Experiment

Crystallisation is a fascinating process. From common observations such as the formation of ice on a window or scale in a kettle, crystallisation is important to virtually every area of science, and lies at the heart of processes as varied as the production of ceramics, pharmaceuticals, fine chemicals, nanomaterials and biominerals. Equally important is the prevention of unwanted crystallisation in the form of weathering, scale or kidney stones. Only by understanding how materials crystallise can we hope to control these processes.

Despite the importance of crystallisation, we still have a poor understanding of many of the mechanisms that underlie this fundamental phenomenon. This is due to the fact that crystallisation is governed by molecular scale processes that are very difficult to study experimentally. For example, while experiments can identify reaction conditions that generate specific crystal polymorphs, they cannot alone explain why this occurred.

This Programme Grant will couple experiment and theory to address this challenge. Our experimental programme brings to the fore such frontier analytical techniques as liquid-phase TEM and functional scanning probe microscopies that will allow us to study the changes in solid and solution during crystallisation as never before. With recent advances in modelling we shall be able to perform simulations of nucleation and growth processes on comparable time- and length-scales, providing a unique opportunity to fully understand crystal nucleation and growth at the nanoscale. These studies will be linked to simpler bulk experiments to provide a holistic view of crystallisation in the real world.

We will use this approach to address six major challenges in the crystallisation of inorganic compounds. Each challenge, as well as being of fundamental importance, is ultimately significant to industry and has practical applications as varied as scale prevention in dishwashers, dental remineralisation and tailoring particle shape for paper coatings. Investigations of homogeneous crystallisation in bulk solution will lay the foundation for our nucleation studies, revealing how we can direct nucleation pathways by varying solution and environmental conditions. We will then build on this work to explore the fascinating question of polymorphism, giving us predictive understanding of conditions which deliver specific crystal polymorphs. Turning then to the ubiquitous phenomenon of surface-directed crystallisation, both theory and cutting-edge analytical methods will bring new understanding of how surfaces - and the changes they cause in the adjacent solution - govern crystallisation. This naturally leads us to a search for effective nucleating agents, which, despite the promises of classical nucleation theory, are known for only a small number of systems. Control of crystal growth to generate particles with defined shapes and sizes is another topic of great industrial importance, and soluble additives are widely used to achieve this goal. By understanding crystal/ additive interactions we aim to pre-select additives to grow crystals with target properties, or to inhibit unwanted crystallisation. Finally, we will study crystallisation within confined volumes; this will ultimately enable us to use confinement to control crystallisation.

These ambitious objectives can only be met within the framework of a Programme Grant, which provides the flexibility and long-term funding to bring together the very different disciplines of theory and experiment. While each of the individual tasks focuses on a distinct problem in crystallisation, they are intimately linked over the entire project by common methods and understanding, and developments in one task will drive advances in others.

This project will deliver major new capability in understanding and controlling inorganic crystallisation under conditions relevant to real world applications. This will be achieved through a combined experimental and theory approach, led by innovations in experimental methods and theory. The impact will therefore be extremely broad, encompassing all who research, manufacture or use crystalline materials in sectors ranging from the Chemical Industry, to Environment, Healthcare, Formulated Products, Oil and Gas, Water, Mining and Advanced Materials.

Industry: As indicated by our industrial collaborators in their letters of support, a greater understanding of crystallisation processes is required in a huge range of applications. The ability to generate specific crystal polymorphs is required in the field of nanomedicine (eg vaterite as soluble drug-delivery agents), while papers coated with aragonite rather than calcite exhibit superior brightness, opacity and strength. Nucleants in washing detergent can reduce crystal deposition on clothing, while the remediation of buildings from weathering relies on crystallisation in porous media. We need to enhance the mechanical properties of building materials such as gypsum, while controlling crystallisation on surfaces is critical to issues as diverse as scale inhibition in heating systems and oil wells, and bone and tooth regeneration. These are all topics addressed in the research programme, where direct collaboration with our industrial partners Proctor and Gamble, Unilever, BP, Lubrizol and Saint Gobain will ensure that technological and economic impact are achieved. Members of the consortium have had considerable success in translating research results to end-users and this embeds valuable experience in the Programme and provides a model that could be followed.

Training: The training and mentoring of early-stage researchers is an essential part of the project. They will acquire a wide range of technical and transferable skills, which will be of value both during this project and in their subsequent careers in industry and academia. We also place a high priority on training in communication and engagement with end users. The project will improve staff skills (science and team-working) via collaboration, through visits and secondments to our academic collaborators and through interactions with industry partners.

Dissemination: Industry and interest groups will be engaged via multiple channels, including our annual "Crystallisation day", specialist workshops, reports to learned societies and policy-makers, through social media, briefing documents and our web presence. We will promote new opportunities for academic-academic and academic-industry partnerships, beyond the consortium and partners. In this way we will seek to build a network for the benefit of the UK as a whole in the short, medium and long-terms. Our results will be published (after IP protection if necessary) in leading journals and presented at national and international scientific meetings. Papers will be available on the open access portals of our institutions and we will archive data in accordance with RCUK best practice.

Outreach and Advocacy: Crystallisation lends itself to impact through public engagement and outreach. All our institutions have well-established outreach programmes including annual Festivals of Science and presentations for teachers/sixth formers and all have dedicated academic outreach officers. We will also exploit all opportunities available to promote advocacy for the Engineering and Physical Sciences within the UK. As the project embodies fundamental interdisciplinary science whilst also being strongly linked to issues of major public interest such as healthcare and the environment, it will be an excellent vehicle for engaging decision makers. We will also empower our industrial partners to act as advocates for the promotion of the project's science and activities.