In traditional centrifugal microfluidic platforms
pumping is restricted to outward fluid flow, resulting in
potential real estate issues for embedding complex microsystems.
To overcome the limitation, researchers utilize
hydrophilic channels to force liquids short distances back
toward the disk center. However, most polymers used for
CD fabrication are natively hydrophobic, and creating
hydrophilic conditions requires surface treatments/specialized
materials that pose unique challenges to manufacturing
and use. This work describes a novel technology that
enjoys the advantages of hydrophilic fluidics on a hydrophobic
disk device constructed from untreated polycarbonate
plastic. The method, termed suction-enhanced
siphoning, is based on exploiting the non-linear hydrostatic
pressure profile and related pressure drop created along the
length of a rotating microchannel. Theoretical analysis as
well as experimental validation of the system is provided.
In addition, we demonstrate the use of the hydrostatic
pressure pump as a new method for priming hydrophobicbased
siphon structures. The development of such techniques
for hydrophobic fluidics advances the capabilities of
the centrifugal microfluidic platform while remaining true
to the goal of creating disposable polymer devices using
feasible manufacturing schemes.