Background
Normally, emulsions are designed to last as long as possible. This is vital for everyday emulsions such as paints, pharmaceutical formulations and ice cream. However, here in the Fielden group, we think this is boring, so instead we make emulsions that destroy themselves.
We use organic supramolecular chemistry to create a molecular tug-of-war, controlling how molecules move into and out of tiny oil droplets within emulsions. By understanding how and why emulsions break down, we aim to turn their instability into a powerful tool for controlling chemistry.
Our goal is to transform simple mixtures of oil and water into smart, dynamic chemical systems. By controlling which molecules enter and leave droplets, we can influence where chemistry happens, when it happens and what happens next. This opens up exciting possibilities, from developing more sustainable chemical reactions and purifying waste streams to releasing pharmaceuticals on demand and creating entirely new ways to transport molecules.
The project
This PhD project focuses on Ostwald ripening, our method of choice for destroying emulsions. Ostwald ripening occurs when oil molecules diffuse from smaller droplets to larger ones, reducing the total surface area of the emulsion. While this process causes major headaches for industry by destabilising pharmaceutical formulations and even making ice cream crunchy over time, we see an exciting opportunity.
Using light-responsive molecular switches, this project will explore how to harness Ostwald ripening rather than simply suppressing it. You will synthesise and characterise molecular switches, investigate how they interact with light, and incorporate them into emulsions. By monitoring changes in droplet size over time, you will establish how the switches influence the rate and direction of oil diffusion, with the ultimate aim of controlling when and how emulsions break down.
Training and mentoring
The successful candidate will be based in the Fielden Group (www.fieldengroup.net). They will gain broad experience in organic synthesis, emulsion formulation, photochemistry, nanoparticle characterisation, NMR and electron microscopy. You will have opportunities to collaborate with other research groups to gain expertise in SAXS, SANS and microscopy, attend conferences, and shape the direction of your own project.
Students in the group receive close mentoring in project design, writing, and presentation skills. Thanks to support from an ERC Starting Grant and a Royal Society Dorothy Hodgkin Fellowship, there is additional enhanced funding for training and travel.
Application process
Interested candidates should contact Dr Fielden by email in the first instance with a copy of their CV and a covering letter outlining their research interests. Applicants should have obtained a strong Master's degree in chemistry or a related discipline. There is no closing date but please apply as soon as possible since the position will be filled as soon as the right candidate is found.
The School of Chemistry is keen to achieve a gender and diversity balance across the School and welcome applicants from all backgrounds. The School holds an Athena SWAN Silver Award, which recognises its work in promoting women’s careers in STEM in higher education.
Funding notes:
Due to funding restrictions, non-self-funded applicants not eligible for UK home fee status will only be considered in exceptional circumstances. Self-funded students are always welcome to contact Steve.
References:
- Aggregate 2025, 6, e70116 – doi.org/10.1002/agt2.70116
- Chem. Eur. J. 2025, 31, e202404387 – doi.org/10.1002/chem.202404387
- Angew. Chem. Int. Ed. 2024, 63, e202320095 – doi.org/10.1002/anie.202320095
- JACS 2024, 146, 18781–18796 – doi.org/10.1021/jacs.4c03314
