Ferrofluidic Pumps

Ferrofluid plugs transported by magnetic fields can be used for pumping liquids through channels. These pumps can be cheap and easy to implement. The pumped liquid should be immiscible with the ferrofluid. Hydrophobic ferrofluids can be used for pumping aqueous solutions. Figure 7.13 shows the principle of a circular ferrofluid pump. It consists of two... 

Figure 7.13 The principle of a circular ferrofluidic pump. Two magnets (M) are employed to manipulate ferrofluid plugs in a circular microchannel. One magnet is moving and another is stationary...

A ferrofluidic magnetic micropump was constmcted on a Si chip. Operation relies on the use of magnetically actuated plugs of ferroliquid (a suspension of nano-sized ferromagnetic particles), which is immiscible with the pumped fluid [301],... 

The following examples present the utilization of the high magnetic gradient and temperature gradient on the microscale for pumping ferrofluids. 

Continuous Pumping of Ferrofluid in a MicroChannel Using a Temperature Gradient... 

The experimental results show that ferrofluids needs more research efforts in micro pumping, and magnetic actuation can be an appropriate alternative for more common techniques such as electromechanical, electrokinetic, and piezoelectric actuation methods. 

While a linear pump can easily be bruit up from two or more basic actuation units, microscale rotary mechanisms face significant fabrication challenges. Accordingly, rotary peristaltic micropumps have seen very limited implementation. While several rotary mechanical micropumps are described in the literature (e.g., see the summaries in Refs. [1, 3], and [2]), to our knowledge there is only one example in the literature of a true rotary peristaltic micropump Kim et al. (Sensors and Actuators A 128 43—51, 2006) use a sflicmie membrane for the deformable charmel surface and a rotating ferrofluid plug... 

Ferrofluids In Microchannels, Figure 7 Concept of magnetocaloric pumping... 

Hartshorne H, Backhouse CJ, and Lee WE 2004 Ferrofluid-based microchip pump and valve. Sens. 

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