Multiscale Thermofluids

Membrane-based processes for water treatment, such as reverse osmosis (RO), hold promise in tackling water scarcity locally and globally. Nevertheless, conventional polyamide membranes for RO exhibit low rejection of Small, charge-Neutral Contaminants (SNCs), which endanger human health and biota.

Progress towards highly selective membranes has been hindered by insufficient understanding of the mechanisms that underlie separation efficiency: how water and contaminants sorb into, and diffuse through, polyamide membranes. Both contaminant sorption and transport require a molecular-level treatment, at far higher resolution than is afforded by conventional (continuum) membrane transport models.

Using molecular dynamics (MD) simulation and free energy calculations, this project aims to computationally design highly selective RO membranes by elucidating the mechanisms governing SNC sorption and transport. The project will focus on SNCs that are insufficiently rejected by state-of-the art RO membranes, e.g., boric acid, a toxic constituent of seawater, and N-nitrosodimethylamine (NDMA), a carcinogenic disinfection by-product whose insufficient removal during RO-based wastewater reuse (rejection ~ 60%) demands additional, and costly, advanced oxidation processes (e.g., high-energy UV).

The specific objectives of this project are:

• Objective 1. To gain molecular-level insight into the hydration layer at the polyamide-water interface, to understand how interfacial water molecules determine SNC sorption and transport.
• Objective 2. To elucidate the role of interfacial chemistry in SNC sorption to polyamide, in order to computationally develop surface coatings to bolster SNC rejection, and thus establish structure-property-performance relations linking coating composition with SNC rejection.
• Objective 3. To characterise the transport mechanisms of SNCs through polyamide, to enable transport models to quantify the trade-off between contaminant rejection and water permeance.

Simulation insights emerging from this project will enable membrane manufacturers to develop highly selective RO membranes. These materials will lower the cost of seawater desalination and wastewater recycling by RO, in addition to producing safer product water for humans and ecosystems.

Research and Training

The successful applicant will conduct research in the School of Engineering at the University of Edinburgh, under the co-supervision of Dr Santiago Romero-Vargas Castrillón and Dr Rohit Pillai. The student will have access to a wide range of computational facilities, including ARCHER2, the UK’s national supercomputer. Educational and research opportunities afforded by this project include:

• Training in state-of-the-art molecular simulation technique
• Close mentoring through regular meetings, as well as interactions with other investigators at the Institute of Multiscale Thermofluids (IMT) and the Institute for Infrastructure and Environment (IIE) at Edinburgh
• The opportunity to attend national and international scientific conferences to disseminate your result
• Strong emphasis and support to publish research results in leading scientific journals, which will kickstart your career in academia or industry

The University of Edinburgh is committed to equality of opportunity for all its staff and students, and promotes a culture of inclusivity. Please see details here: https://www.ed.ac.uk/equality-diversity

This is a challenging and scientifically ambitious project, requiring a student who is dedicated and enthusiastic about asking, and tackling, fundamental questions. The successful applicant will have been awarded an undergraduate degree at the time of appointment (2:1 or above, preferably supported by an MSc) in chemical engineering, mechanical engineering, chemistry, physics, materials science, or a cognate field. A strong background in mathematics and physics is required, as well as interest in molecular simulation. Prior research experience in modeling and simulation is highly desirable.

Further information on English language requirements for EU/Overseas applicants.

Applications are welcomed from self-funded students, or students who are applying for scholarships from the University of Edinburgh or elsewhere, as explained below.

PhD studentships managed by the School of Engineering at the University of Edinburgh are available every year through a competitive process.

Applicants interested in applying for a University-administered award should e-mail the supervisors (Santiago@ed.ac.uk, R.Pillai@ed.ac.uk) as soon as possible to begin discussions, explaining how your experience meets the Applicant Requirements given above. Application deadlines vary from mid-January to late March.

Please note that most studentships are available only to Home Students (International students not eligible.)

To qualify as a Home student, you must fulfil one of the following criteria:

• You are a UK student

• You are an EU student with settled/pre-settled status who also has 3 years residency in the UK/EEA/Gibraltar/Switzerland immediately before the start of your Programme.

Further information and other funding options.

Condensation is a heat transfer process in which a vapor releases energy/heat as it changes its phase to become a liquid, which typically occurs when the vapor is cooled below its dew temperature, often upon making contact with a cooler surface. This process is critical in numerous applications, including in HVAC systems, power generation, and refrigeration. The effectiveness of dropwise condensation in transferring heat makes it essential in condensers, where minimizing the surface area for dropwise condensation and optimizing conditions for heat transfer can significantly enhance system efficiency. Techniques such as enhancing surface properties or controlling fluid dynamics are often employed to maximize the rate of heat transfer during the condensation process.

Recently, we developed new techniques to modify surfaces with regions that can tune the surface properties and control the fluid dynamics of condensing droplets via patterned liquid-like surfaces, which are based on Slippery Covalently Attached Liquid-like Surfaces (SCALS). In this experimental project, you will tackle questions involving condensation on patterned liquid-like surfaces: we are interested in understanding how the different SCALS chemistries and the nature of the patterning affect condensation and heat transfer and help to maintain a stable heat flux during condensation phase-changes. This will require parametric and methodological studies and by answering questions like these, you will be pushing the boundaries of knowledge in this field and kick-start your postgraduate career.

We expect that you will have a good degree in Engineering or Physics with an experimental and modelling background. We are particularly interested to hear from applicants with experience in surface science, fluids dynamics and fluid mechanics and/or phase change.

If successful, you will become a member of the Wetting, Interfacial Sciences and Engineering WISE Group within the Institute for Multiscale Thermofluids at the School of Engineering. You will join a vibrant community of PhD students, postdoctoral research associates and academics working in various aspects of surfaces and wetting, and will develop as a scientist benefiting from our track record, which includes publications in top journals, international collaborations and contributions to key international conferences.

The University of Edinburgh is committed to equality of opportunity for all its staff and students, and promotes a culture of inclusivity: https://www.ed.ac.uk/equality-diversity

Minimum entry qualification - an Honours degree at 2:1 or above (or International equivalent) in Engineering or Physics with an experimental and modelling background, possibly supported by an MSc Degree. We are particularly interested to hear from applicants with experience in surface science, fluids dynamics and fluid mechanics and/or phase change.

Further information on English language requirements for EU/Overseas applicants.

Applications are welcomed from self-funded students, or students who are applying for scholarships from the University of Edinburgh or elsewhere.

Further information and other funding options.

The interaction of droplets with structured surfaces is extremely important in microfluidics, with target applications in medical diagnostics, self-assembly and printing. In this project you will study the dynamic interactions of droplets with structured solid surfaces coated by a thin liquid lubricant layer. Depending on your skills and interests, you will tackle questions about the fluid dynamics of this system using experimental/computational approaches, or a combination of both.

If successful, you will become a member of the Wetting, Interfacial Sciences and Engineering Group within the Institute for Multiscale Thermofluids at the School of Engineering. You will join a vibrant community of PhD students, postdoctoral research associates and academics working in various aspects of surfaces and wetting, and will develop as a scientist benefiting from our track record, which includes publications in top journals, international collaborations and contributions to key international conferences.

Informal queries can be directed to Dr Rodrigo Ledesma-Aguilar (Rodrigo.ledesma@ed.ac.uk)

The University of Edinburgh is committed to equality of opportunity for all its staff and students, and promotes a culture of inclusivity: https://www.ed.ac.uk/equality-diversity

Minimum entry qualification - an Honours degree at 2:1 or above (or International equivalent) in a relevant science or engineering discipline, possibly supported by an MSc Degree.

We expect that you will have a good degree in Engineering or Physics with an experimental or computational modelling background. We are particularly interested to hear from applicants with experience in surfaces and fluid mechanics.

Further information on English language requirements for EU/Overseas applicants.

Applications are welcomed from self-funded students, or students who are applying for scholarships from the University of Edinburgh or elsewhere.

Further information and other funding options.

Friction is a key limiting factor affecting the motion of liquids in contact with solid surfaces. When water droplets interact with a solid surface, friction can severely limit the speed at which they move, or hamper their motion altogether. Fundamentally, friction between droplets and solid forces is an open field of research in fluid mechanics, with important applications in a range of fields, from microfluidics to self-cleaning and heat transfer.  

Recently, we have initiated research on the interaction between droplets and liquid-like surfaces. These are surfaces created by grafting polymer chains to a solid substrate, thus creating an ultrasmooth surface. In this project you will study the dynamics of droplets on patterned LLS, where a surface topography, or a chemical pattern, is applied. The scope of the project will be experimental, theoretical, or a combination of both, depending on your specific skill set. By addressing the questions of this project, you will be pushing the boundaries of knowledge in this new field and kick-start your postgraduate career.

If successful, you will become a member of the Wetting, Interfacial Sciences and Engineering Group within the Institute for Multiscale Thermofluids at the School of Engineering. You will join a vibrant community of PhD students, postdoctoral research associates and academics working in various aspects of surfaces and wetting, and will develop as a scientist benefiting from our track record, which includes publications in top journals, international collaborations and contributions to key international conferences.

The following academic team will be part of your supervision team:

Principal supervisor:Rodrigo Ledesma Aguilar: https://www.eng.ed.ac.uk/about/people/dr-rodrigo-ledesma-aguilar

Assistant supervisors:Gary Wells: https://www.eng.ed.ac.uk/about/people/dr-gary-wellsProfessor Glen McHale: https://www.eng.ed.ac.uk/about/people/professor-glen-mchale

Informal queries can be directed to Dr Rodrigo Ledesma-Aguilar (Rodrigo.ledesma@ed.ac.uk)

The University of Edinburgh is committed to equality of opportunity for all its staff and students, and promotes a culture of inclusivity: https://www.ed.ac.uk/equality-diversity

Minimum entry qualification - an Honours degree at 2:1 or above (or International equivalent) in a relevant science or engineering discipline, possibly supported by an MSc Degree.

We expect that you will have a good degree in Engineering or Physics with an experimental and/or modelling background. We are particularly interested to hear from applicants with experience in surfaces and fluid mechanics.

Further information on English language requirements for EU/Overseas applicants.

Applications are welcomed from self-funded students, or students who are applying for scholarships from the University of Edinburgh or elsewhere.

Further information and other funding options.

The wetting behaviours of liquids on solid surfaces play an important role for a wide range of engineering applications, including coatings, electronics, oil recovery, microfluidics, and inkjet printing. For many of these applications, the key challenge is to control the static and dynamic wettability of a given substrate against various liquids. To achieve such control, especially over the full range of wettability landscape, surface chemistry, while crucial, is inadequate by itself. Recent works have shown that novel surfaces with exceptional wetting properties (often termed as superwettability) can be designed by introducing roughness, lubrication, chemical heterogeneities, and tuning the elasticity of the substrate.

The underlying theme of this PhD project is to study the rich interplay between fluid flow dynamics, surface chemistry, geometry, roughness, and solid elasticity in the context of wetting phenomena. Depending on the interests of the student, they can focus on modelling or combine modelling and experiments to develop engineering design principles for structured surfaces with superwettability properties. We will consider both model surfaces with regular patterns (e.g., posts, holes) and non-ideal, industrially relevant substrates (e.g., complex fibres, meshes). This project will also involve collaborations with our international experimental and industrial partners, Dr.-Ing. Hutomo Suryo Wasisto (Infineon Technologies AG, Germany) and Prof. Kuwat Triyana (Universitas Gadjah Mada, Indonesia), to explore how these design principles can be exploited for applications in microelectromechanical system (MEMS) and sensor technologies.

It is expected that the applicant will have a good degree in Engineering, Physics, Mathematics, or any other related subject. We are particularly keen to hear from applicants who want to develop expertise in fluids, surfaces, and/or simulations using high performance computing. Prior experience in any of these areas is useful but not a necessity to apply.

The student will join Prof Halim Kusumaatmaja’s group which will move to the Institute for Multiscale Thermofliuds at the University of Edinburgh in May 2024. The student will also benefit from a vibrant community of PhD students, postdoctoral research associates and academics working in various aspects of surfaces and wetting in Edinburgh.

The University of Edinburgh is committed to equality of opportunity for all its staff and students, and promotes a culture of inclusivity. Please see details here: https://www.ed.ac.uk/equality-diversity

Further information about Prof Halim Kusumaatmaja’s group can be found in: https://sites.google.com/site/kusumaatmaja/home 

Minimum entry qualification - an Honours degree at 2:1 or above (or International equivalent) in a relevant science or engineering discipline, possibly supported by an MSc Degree. Further information on English language requirements for EU/Overseas applicants.

Applications are welcomed from self-funded students, or students who are applying for scholarships from the University of Edinburgh or elsewhere.

Further information and other funding options.