Formation and manipulation of ferrofluid droplets at a microfluidic T-junction
Kang, Tae Goo
Date of Issue2010
School of Mechanical and Aerospace Engineering
This paper reports the formation and manipulation of ferrofluid droplets at a microfluidic T-junction in the presence of a permanent magnetic field. A small circular permanent magnet with a diameter of 3 mm is used to control the size of the ferrofluid droplets within a microfluidic device. In the absence of a magnetic field, the size of the ferrofluid droplets decreases linearly with the increase of the flow rate of the continuous phase. In the presence of a magnetic field, the size of the droplets depends on the magnetic field strength, magnetic field gradient and the magnetization of the ferrofluid. The magnetic field strength is adjusted in our experiment by the location of the magnet. The induced attractive magnetic force affects the droplet formation process leading to the change in the size of the formed droplets. Experimental observation also shows that the relative change in the size of the droplet depends on the flow rate of the continuous phase. Furthermore, the paper compares the evolving shape of the ferrofluid droplet during the formation process with and without the magnetic field.
Journal of micromechanics and microengineering
© 2010 IOP Publishing Ltd. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of Micromechanics and Microengineering, IOP Publishing Ltd.. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [DOI: http://dx.doi.org/10.1088/0960-1317/20/4/045004].