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Published December 2008 | Published
Journal Article Open

Floating-Disk Parylene Microvalves for Self-Pressure-Regulating Flow Controls

Abstract

This paper presents the first parylene-based floating-disk microvalve with self-pressure-regulating characteristics for various microfluidic applications. By incorporating a free-floating disk diaphragm with no anchoring/tethering structures to constrain its movement, the microvalve realizes configurable pressure-based flow-shunting functions in a stand-alone fashion. Its passive operation eliminates the need for power sources or the external actuation of the device. A multilayer polymer surface-micromachining technology is utilized for device fabrication by exploiting parylene C (poly-chloro-p-xylylene) as the biocompatible structural material for high mechanical compliance as compared with other conventional thin-film materials. Experimental results successfully demonstrate that the in-channel microvalves control water flows in the following two different shunt designs: 1) a nearly ideal regular check valve with zero forward-cracking pressure, zero reverse leakage, and 1.25 x 10^13 - 2.09 x 10^13 N·s/m^5 (0.03–0.05 psi·min/μL, 1.55–2.59 mmHg·min/μL) of fluidic resistance; and 2) a pressure–bandpass check valve with 0–100 mmHg and 0–10 μL/min of pressure and flow rate regulation ranges, respectively, as well as 4.88 x 10^13 N·s/m^5 (0.12 psi·min/μL, 6.08 mmHg·min/μL) of fluidic resistance in the forward conductive region. Such a biocompatible and implantable microvalve has the great potential of being integrated in microfluidic systems to facilitate effective microflow control for lab-on-a-chip and biomedical applications.

Additional Information

© 2008 IEEE. Reprinted with permission. Manuscript received March 3, 2008; revised June 23, 2008. First published October 28, 2008; current version published December 4, 2008. This work was supported in part by the Engineering Research Centers Program of the National Science Foundation under NSF Award EEC-0310723 and in part by Bausch and Lomb. Earlier versions of this paper were presented at the 20th IEEE International Conference on Micro Electro Mechanical Systems, Kobe, Japan, January 21–25, 2007, and the 21st IEEE International Conference on Micro Electro Mechanical Systems, Tucson, AZ, January 13–17, 2008. Subject Editor Y. Zohar. The authors would like to thank J. Shih for his valuable comments on fluidic measurements and analysis and T. Roper for his fabrication assistance.

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August 22, 2023
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October 17, 2023