Molecular Solid Solutions (MoSS): From Concept to Applications

This PhD project will deliver a new strategy – the formation of solid solutions of organic molecules (molecular solid solutions, MoSS) – to control the structure and properties of molecular crystals, where these form the basis of most pharmaceuticals and agrochemicals.

<p style="margin-top:11px; text-align:justify"><strong>Background:</strong> Solid solutions are created when dopants (molecules, atoms etc) are incorporated within the structure of a host crystal.  They are well-established for metals and inorganic crystals where the introduction of tiny amounts of dopants can have enormous effects on properties, such as in the doping of iron with carbon to form steel. By comparison, MoSS have received little attention.  However, exciting recent data by our team demonstrate their enormous potential, where doping of molecular crystals can alter their (i) structure and stability, (ii) morphologies, (iii) properties such as solubility and resistance to fracture and (iv) the rate of growth.  These changes are currently hard to predict, where subtle differences in the structure of the dopants can lead to no MoSS formation at all, or MoSS with different structures and properties.</p> <p><strong>Strategy: </strong>Our ultimate goal is to establish the design rules that govern the formation of MoSS and their structure-property relationships such that we can tune the structures and properties of molecular crystals in a predictable way by creating MoSS and thus create crystals with superior properties.  The project will use a range of approaches to achieve this goal.</p> <p>(1)  High-throughput synthesis and screening methods will be used to explore MoSS formed from different host and dopant molecules, at different host/ dopant ratios. Workflows will be developed and refined to explore and characterise MoSS host/dopant systems and reaction conditions, revealing the relationships between the synthesis conditions and the structure and composition of MoSS crystals.</p> <p>(2)  Understanding the mechanisms by which dopants are incorporated into host crystals will enable us to further control the formation of MoSS.  The impact of dopants on nucleation kinetics, the crystallisation pathway and growth of MoSS crystals will be investigated using microfluidic devices and levitated droplets.</p> <p>(3)  In collaboration with our project partners at Durham, Manchester and Syngenta, Machine Learning methods will be used to interrogate the experimental data, predicting key outcomes such as the likelihood of MoSS formation and crystal structures.</p> <p>(4)  In the final year of the PhD programme, a real-world agrochemical supplied by Syngenta will be studied. This will be done via a placement at Syngenta, giving experience of working in a leading company.</p> <p><strong>Training Environment:</strong> The project is co-funded by Syngenta and the EPSRC and is associated with a recently-announced £7M Programme Grant involving the Universities of Leeds, Durham and Manchester. The successful applicant will gain hugely from being part of this framework, where the Early Stage Researchers on the grant form a close group and have opportunities to collaborate widely, to attend a broad range of training opportunities, project meetings and outreach events. </p>

<p>Formal applications for research degree study should be made online through the University’s website. Please state clearly in the Planned Course of Study section that you are applying for <em><strong>EPSRC DTP Engineering & Physical Sciences</strong></em> (if you do not apply under this programme code, your application will not be considered), in the research information section that the research degree you wish to be considered for is <strong>Molecular Solid Solutions (MoSS): From Concept to Applications</strong> as well as <a href="https://eps.leeds.ac.uk/chemistry/staff/4202/professor-fiona-meldrum">Professor Fiona Meldrum</a> as your proposed supervisor<em><strong> </strong></em>and that the funding you wish to be considered for is <em><strong>EPSRC Faculty Doctoral Landscape Award 2026/27: Chemistry</strong></em>.</p> <p>Applications will be considered after the closing date of Friday 27 February 2026.  Potential applicants are strongly encouraged to contact supervisors for an informal discussion before making a formal application. We also advise that you apply at the earliest opportunity as the application and selection process may close early, should we receive a sufficient number of applications or that a suitable candidate is appointed.</p> <p>Please note that you must provide the following documents in support of your application by the closing date of Friday 27 February 2026:</p> <ul> <li>Full Transcripts of all degree study or if in final year of study, full transcripts to date including grading scheme</li> <li>Personal Statement outlining your interest in the project</li> <li>CV</li> </ul> <p>If English is not your first language, you must provide evidence that you meet the University's minimum English language requirements (below).</p> <p><em>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</em></p>

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.

<p>A highly competitive EPSRC Faculty Doctoral Landscape Award, in collaboration with Syngenta, providing full academic fees, together with a tax-free maintenance grant at the standard UKRI rate (£20,780 in academic session 2025/26) for 3.5 years.  Training and support will also be provided.</p> <p>This opportunity is open to UK applicants only.  All candidates will be placed into the EPSRC Faculty Doctoral Landscape Award Competition and selection is based on academic merit.</p> <p>Please note that there is 1 funded place available.  If you are successful in securing an academic offer for PhD study, this does not mean that you have been successful in securing an offer of funding.</p> <p>Please refer to the <a href="https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ukcisa.org.uk%2F&data=05%7C02%7CJ.S.Hewer%40leeds.ac.uk%7C07632c93c06a442dca3d08ddfc172939%7Cbdeaeda8c81d45ce863e5232a535b7cb%7C0%7C0%7C638943898649349324%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=nylGSov8jOc7hr6X%2FmfnfQPecbVUnGqgoSqVgPGy5K0%3D&reserved=0">UKCISA</a> website for information regarding Fee Status for Non-UK Nationals</p>

<p>For further information about your application, please contact PGR Admissions by email to <a href="mailto:phd@engineering.leeds.ac.uk">phd@engineering.leeds.ac.uk</a></p> <p>For further information about this project, please contact Professor Fiona Meldrum by email to <a href="mailto:F.Meldrum@leeds.ac.uk">F.Meldrum@leeds.ac.uk</a></p>