Tuneable electrohydrodynamics of core-shell graphene oxide vortex rings

Yizhen Shao, Kaiwen Nie, Maria Iliut, Finn Box, Dai Luan, Yuan Shen, Weimiao Wang, William Sampson, Ingo Dierking, Aravind Vijayaraghavan

Research output: Contribution to journalArticlepeer-review


The vortex ring (VR) effect occurs when fluid droplets impact on another fluid, leading to toroidal flow within the impacting droplet due to viscous friction, resulting in a wide variety of flow-induced morphologies. When applied to dispersions of 2-dimensional materials, such as graphene oxide (GO) in water, the VR effect can be used to generate 3-dimensional assemblies of GO flakes. Here, we have taken advantage of the surface charge on GO flakes in water, interacting with cationic aqueous surfactant systems, to generate an electrohydrodynamic VR effect. This yields GO hydrogel and aerogel microparticles with complex axially symmetric shapes, with a core-shell structure featuring a shell of aligned GO flakes. Using high frame-rate optical imaging, we have captured the real-time self-assembly of GO core-shell hydrogel microparticles shaped like spheres, donuts and jellyfish. We describe, both qualitatively and quantitatively, the electrohydrodynamics that drive the formation of such shapes. We also demonstrate how the underlying processes can be tuned by varying parameters such as GO concentration, flake size and drop velocity, and surfactant chemistry and concentration to produce a wide variety of controllable exterior and interior morphologies. Indeed, we show that the formation regimes of the different shapes are determined by dimensionless Weber and Ohnesorge numbers. Lastly, we demonstrate how these microparticles can be used for the efficient adsorption and removal of anionic contaminants in water, with tuneable adsorption capacity.
Original languageEnglish
JournalJournal of Molecular Liquids
Publication statusAccepted/In press - 26 Jan 2023


Dive into the research topics of 'Tuneable electrohydrodynamics of core-shell graphene oxide vortex rings'. Together they form a unique fingerprint.

Cite this