Probing defects in molecular materials: From polymers to metal–organic frameworks

Molecular materials span glasses, semi-crystalline polymers, and highly crystalline framework materials and molecular crystals. They are bound to a common cause in materials science by their characteristic molecular sub-components: their strong covalent bonds strongly direct interatomic structure but much weaker and often anisotropic interactions drive intermolecular interactions. Complex defects and disorder can appear in the domain of molecular packing. Yet compared to inorganic materials our understanding of the details of such defect and disorder modes remains in its infancy. This project will seek to advance state-of-the-art microscopy, diffraction and total scattering, and spectroscopy techniques to unravel atomic and molecular pictures in what are characteristically non-periodic features of these materials. <br /> <br /> Defect-engineering in metal–organic frameworks (MOFs) has arisen as a key route to modulating their functional properties such as by controlling their pore size distributions. Likewise, controlling the crystallisation of many polymers is critical to performance in energy materials (organic light emitting diodes, photovoltaics, and emerging electronics) as well as in determining their mechanical properties. The precise, microscopic mechanisms of these disorder types—known to determine functional properties at the macroscopic length scale—remains obscured. A few instances show significant promise: Our group has developed nanobeam electron diffraction in the scanning transmission electron microscopes (STEM) to reveal coherent defect domains in MOFs [1], rotational disorder in crystal-amorphous MOF composites [2], as well as dislocations in molecular crystals [3] and molecular packing in polymer semiconductors [4]. <br /> <br /> This project will take these tools as a launch point to develop the next generation of tools for the characterisation of defects and disorder in molecular materials. Key routes to develop over the project may include cryogenic cooling of samples to examine hydration or dehydration, precession electron diffraction for electron beam pair distribution function analysis, and diffuse scattering analysis for molecular vibrational mode analysis (phonons). The project includes opportunities to tailor directions to the interests of the researcher and adapt to discoveries of previously unknown disorder types along the way. We are keen to support and develop an inclusive community of researchers, with the aim for equity for marginalised researchers. If you are interested, please email Sean Collins (s.m.collins@leeds.ac.uk) for informal inquiries. <br /> <br /> [1] D.N. Johnstone et al. J. Am. Chem. Soc. 142 (2020) 13081–13089. <br /> [2] A.F. Sapnik et al. Commun Chem 6 (2023) 1–12. <br /> [3] S.T. Pham et al. ArXiv preprint (2023) https://doi.org/10.48550/arXiv.2308.16589.<br /> [4] A.J. Sneyd et al. Science Advances 7 (2021) eabh4232.

<p style="margin-bottom:11px"><strong>Additional information</strong></p> <p>The project will have a primary focus on structural and chemical characterisation. The PhD researcher will receive training to drive forward their research using approaches including electron diffraction, pair distribution function analysis, and vibrational, optical, and core ionisation spectroscopy. The project will draw on materials science, chemistry, physics, and engineering principles. Applications are welcome from undergraduate degrees in any related field.</p> <p>The advanced electron microscopy techniques used in the project will involve the use of equipment at the University of Leeds and the Leeds Electron Microscopy and Spectroscopy (LEMAS) Centre at the <a href="https://www.leeds.ac.uk/bragg-centre-materials-research">Bragg Centre for Materials Research</a>. Instrumentation at LEMAS includes a new Tescan Tensor dedicated scanning transmission electron microscope, one of the first two installed in the world, as well as cryogenic plunge-freezing and cryo-transfer, focused ion beam facilities, and capabilities for electron beam spectroscopy, diffraction, and tomography (three-dimensional imaging).</p> <p>The PhD researcher working on this project will join an enthusiastic and creative team of researchers working across a range of topics from electron microscopy of organic semiconductors and small molecule organic crystals to MOF synthesis. The research group is joint between the School of Chemical and Process Engineering and the School of Chemistry at the University of Leeds. </p>

<p>Formal applications for research degree study should be made online through the <a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">University's website</a>. Please state clearly in the Planned Course of Study section that you are applying for <em><strong>EPSRC DTP Engineering & Physical Sciences</strong></em> and in the research information section that the research degree you wish to be considered for is <em><strong>Probing defects in molecular materials: From polymers to metal–organic frameworks</strong></em> as well as <a href="https://eps.leeds.ac.uk/chemical-engineering/staff/8179/dr-sean-collins">Dr Sean M. Collins</a> as your proposed supervisor. P<em><strong>lease state clearly in the Finance section that the funding source you are applying for is EPSRC Doctoral Landscape Award 2025/26: Chemical & Process Engineering.</strong></em></p> <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> <p style="margin-bottom:11px">Applications will be considered after the closing date.  Potential applicants are strongly encouraged to contact the 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 28 February 2025:</p> <ul> <li>Full Transcripts of all degree study or if in final year of study, full transcripts to date</li> <li>Personal Statement outlining your interest in the project</li> <li>CV</li> </ul>

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 class="MsoNoSpacing">A highly competitive EPSRC Doctoral Landscape Award providing full academic fees, together with a tax-free maintenance grant at the standard UKRI rate (£19,237 in academic session 2024/25) for 3.5 years.  Training and support will also be provided.</p> <p>This opportunity is open to all applicants.  All candidates will be placed into the EPSRC Doctoral Landscape Award Competition and selection is based on academic merit.</p> <p><strong>Important:</strong> Please note that that the award does <em><strong>not</strong></em> cover the costs associated with moving to the UK.  All such costs (<a href="https://www.leeds.ac.uk/international-visas-immigration/doc/applying-student-visa">visa, Immigration Health Surcharge</a>, flights etc) would have to be met by yourself, or you will need to find an alternative funding source. </p> <p>Please refer to the <a href="https://www.ukcisa.org.uk/">UKCISA</a> website for information regarding Fee Status for Non-UK Nationals.</p>

<p>For further information about this project, please contact Dr Sean Collins by email to <a href="mailto:s.m.collins@leeds.ac.uk">s.m.collins@leeds.ac.uk</a></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>