Difference between revisions of "Paper on a disc: balancing the capillary-driven flow with a centrifugal force"
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Revision as of 00:34, 3 October 2011
Entry by Yuhang Jin, AP225 Fall 2011
Hyundoo Hwang, Seung-Hoon Kim, Tae-Hyeong Kim, Je-Kyun Parkb and Yoon-Kyoung Cho, Lab Chip, 2011, 11, 3404.
paper microfluidics, capillary-driven flow, centrifugal forces
Paper microfluidic devices allow passive transport of fluids through capillary force, and carry intrinsic advantages such as low-cost, flexible, and simple fabrication and easiness to store, transport, and dispose. Liquid transport in paper depends on the structure and material of the pre-manufactured paper, and controlling the flow in a continuous and active manner appears rather difficult. This paper presents a novel concept for active control of the flow in paper using a centrifugal force by integrating a paper strip into a disc-shaped centrifugal microfluidic platform and rotating it with various spin speeds. The flow in the paper under different strength of the centrifugal force is characterized. The paper demonstrates the ability to control the flow rate in a programmable manner as well as reverse the flow direction.
Theory, experiments and results
The wicking distance h, shown in Fig. 1, obeys the Darcy's law: