Engineering Surfactant Powders: Drying Dynamics, Structure and Performance

Surfactant powders are everywhere, from household detergents to industrial formulations, but their performance is ultimately determined by how they dry. Alpha-olefin sulfonates (AOS) are widely used anionic surfactants, valued for their robustness and versatility, yet the fundamental links between formulation, drying dynamics, and final powder performance remain poorly understood. Drying is a highly dynamic process, involving evolving concentration gradients, interfacial phenomena, and phase transitions that shape particle morphology, internal structure, and dissolution behaviour. Gaining control over these processes is key to designing better-performing, more efficient surfactant products.<br /> <br /> This collaborative PhD project, supported by the University of Leeds and Innospec, offers the opportunity to uncover the science that governs how surfactant powders form. The project will deliver new mechanistic insight into AOS drying, connecting formulation chemistry and processing conditions to structure and performance, with direct relevance to industrial manufacturing.<br /> <br /> At the heart of the research is a unique acoustic levitation platform that allows individual droplets to be dried without contact, enabling real-time observation of shape changes, crust formation, and internal structural evolution. This will be combined with state-of-the-art small- and wide-angle X-ray scattering (SAXS/WAXS) to probe nanoscale structure development during drying, including phase transitions and crystallisation. Time-resolved synchrotron SAXS experiments at Diamond Light Source will provide an exceptional window into how droplets transform from liquids into hollow or solid particles. These insights will be linked to key macroscopic properties such as particle morphology, dissolution rate, and rehydration behaviour.<br /> <br /> The student will be based in the School of Chemical and Process Engineering (SCAPE) at the University of Leeds and supported by a highly interdisciplinary supervisory team spanning chemical engineering, mechanical engineering, food science, and industrial formulation science. The project offers access to world-leading experimental facilities, pilot-scale drying equipment, and close industrial collaboration with Innospec, including the opportunity for an industrial placement.<br /> <br /> Alongside advanced technical training, the student will benefit from the EPSRC Doctoral Landscape Award, gaining professional and transferable skills, research ethics training, and opportunities for conference participation and international collaboration. This PhD is ideal for a motivated candidate seeking hands-on experimental research, strong industry engagement, and the chance to make a real impact at the interface of formulation science, manufacturing, and materials physics.<br />

<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> (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 <em><strong>Engineering Surfactant Powders: Drying Dynamics, Structure and Performance</strong></em> as well as <a href="https://eps.leeds.ac.uk/chemical-engineering/staff/346/associate-professor-david-harbottle">Assoc. Prof. David Harbottle</a> as your proposed supervisor and that the funding you wish to be considered for is <em><strong>EPSRC Faculty Doctoral Landscape Award 2026/27: Chemical & Process Engineering</strong></em>.</p> <p>Applications will be considered after the closing date of Monday 30 March 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 Monday 30 March 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 Innospec, 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 this project, please contact Assoc. Prof. David Harbottle by email to <a href="mailto:d.harbottle@leeds.ac.uk">d.harbottle@leeds.ac.uk</a> or by calling +44 (0)113 343 4154.</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>