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Tunable Superparamagnetic Ring (tSPRing) for Droplet Manipulation
Author(s) -
Nasirimarekani Vahid,
BenitoLopez Fernando,
BasabeDesmonts Lourdes
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202100178
Subject(s) - ferrofluid , materials science , superparamagnetism , magnet , chemical physics , nanotechnology , digital microfluidics , magnetic field , microfluidics , dipole , suspension (topology) , ring (chemistry) , ferromagnetism , work (physics) , condensed matter physics , optoelectronics , magnetization , mechanical engineering , physics , chemistry , thermodynamics , mathematics , organic chemistry , electrowetting , quantum mechanics , homotopy , dielectric , pure mathematics , engineering
The manipulation of droplets via a magnetic field forms the basis of a fascinating technology that is currently in development. Often, the movement of droplets with magnets involves adding magnetic particles in or around the droplet; alternatively, magneto responsive surfaces may also be used. This work, presents and characterizes experimentally the formation and properties of a tunable superparamagnetic ring (tSPRing), which precisely adjusts itself around a water droplet, due to liquid–liquid interaction, and enables the physical manipulation of droplets. The ring is made of an oil‐based ferrofluid, a stable suspension of ferromagnetic particles in an oily phase. It appears spontaneously due to the oil–water interfacial interaction under the influence of a magnetic field. The ferrofluid–water interaction resembles a cupcake assembly, with the surrounding ring only at the base of the droplet. The ring is analogous to a soft matter ring magnet, showing dipole repulsive forces, which stabilizes the droplets on a surface. It enables robust, controllable, and programmable manipulation of enclosed water droplets. This work opens the door to new applications in open surface upside or upside‐down microfluidics and lays the groundwork for new studies on tunable interfaces between two immiscible liquids.