Partial-post Laplace barriers for virtual confinement, stable displacement, and >5 cm s(-1) electrowetting transport.
Laplace barriers composed of full-posts or ridges have been previously reported as a mechanism for virtual fluid confinement, but with unstable displacement (capillary fingering or fluid trapping, respectively). A new platform of 'partial-posts' eliminates the disadvantages of full-posts or ridges, while providing ~60-80% open channel area for rapid electrowetting fluid transport (>5 cm s(-1)). The fluid mechanics of partial-post Laplace barriers are far more complex than previous Laplace barriers as it involves two mechanisms: fluid can first begin to propagate either between, or under, the partial-posts. Careful design of channel and partial-post geometries is required, else one mechanism will dominate over the other. The physics and performance of partial-post Laplace barriers are verified using theoretical equations, experimental results, and dynamic numerical modeling.
Novel Devices Laboratory, School of Electronics and Computing Systems, University of Cincinnati, Cincinnati, Ohio 45221, USA.
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E
Kreit
B M
BM
Mognetti
J M
JM
Yeomans
J
J
Heikenfeld