BioMaths Colloquium Series – 2023/24
3 July 2024 – 1pm
Join us at 12:45 for coffee tea and biscuits
Board Room 401 (Computational Foundry, Bay Campus) or Zoom (register here)
Crystal-like structures in microfluidic flows of viscoelastic non-Newtonian suspensions.
Dr Francesco Del Giudice is an Associate Professor in Chemical Engineering, and he is a recognised Chartered Chemical Engineer and a Chartered Scientist. Francesco is the head of the Rheological Microfluidic lab at Swansea University Bay Campus. Francesco’s interests are in Microfluidics and Soft Matter. For instance, we developed innovative solutions to improve the encapsulation of flowing particles using viscoelastic flows in microfluidic devices, and we also developed microfluidic techniques to evaluate rheological parameters not measurable via conventional techniques.
Francesco has the long-term vision of challenging the status quo by introducing disruptive technologies and methodologies across a broad range of fields. We are exploring new methodologies for the manufacturing of materials, while tackling some fundamental questions in multiphase microfluidic flows. We are also implementing machine learning within microfluidic applications. We are also interested in solving new and exciting problems across the broad spectrum of Soft Matter and polymer physics.
Francesco has several roles across national and international institutions, including Functional Chartered Member of the IChemE, ICP Panel member of the IChemE, Concil Member of the British Society of Rheology, and core member of the Institute of Non-Newotnian Fluid Mechanics.
Francesco has several hobbies including reading, classical music, photography, and cycling. He is always open to face new challenges and is keen to lead other people that share his vision. He also acts as a counsellor for colleagues and students that need support.
When particles are added to a continuous liquid matrix, the resulting system is called a suspension. Suspensions are generally considered to be diluted when they stop obeying the Einstein-Stokes relation, which is valid for non-interacting hard spheres. Experimental results from past works showed that this is generally true when the bulk particle concentration is less than around 5% in volume. This finding has been observed when the suspending liquid is either Newtonian (such as water or oil) or non-Newtonian. Non-Newtonian liquids present both viscous and elastic components, with a flow behaviour that departs significantly from the Newtonian liquids.
We here experimentally show that rigid spherical particles with diameter 𝑑≥20 𝜇𝑚 suspended in viscoelastic liquids and flowing in a straight channel having a diameter 𝐷=100 𝜇𝑚 arrange in equally-spaced crystal-like structures caused by the hydrodynamic interactions between consecutive particles even at bulk concentrations as small as 0.25% in volume. Geometrical parameters mainly control the spacing between the particles and the type of viscoelastic suspending liquid. The microfluidic crystal is formed because of a space-time evolution of particle distances while flowing in a straight channel, resulting from the hydrodynamic interactions between consecutive particles mediated by the fluid viscoelasticity. We also observed such crystal-like structures for highly confined Red Blood Cells.
Our results have also been used for practical applications related to improving encapsulation efficiency and providing a platform to explore multi-body interactions among encapsulated objects.