Microfluidics and Nanofluidics

, Volume 6, Issue 6, pp 823–833

A pneumatic micropump incorporated with a normally closed valve capable of generating a high pumping rate and a high back pressure

Research Paper

DOI: 10.1007/s10404-008-0356-7

Cite this article as:
Yang, Y., Hsiung, S. & Lee, G. Microfluid Nanofluid (2009) 6: 823. doi:10.1007/s10404-008-0356-7

Abstract

This study reports on a new pneumatic micropump integrated with a normally closed valve that is capable of generating a high pumping rate and a high back pressure. The micropump consists of a sample flow microchannel, three underlying pneumatic air chambers, resilient polydimethylsiloxane (PDMS) membrane structures and a normally closed valve. The normally closed valve of the micropump is a PDMS-based floating block structure located inside the sample flow microchannel, which is activated by hydraulic pressure created by the peristaltic motion of the PDMS membranes. The valve is used to effectively increase pumping rates and back pressures since it is utilized to prevent backflow. Experimental results indicate that a pumping rate as high as 900 μL/min at a driving frequency of 90 Hz and at an applied pressure of 20 psi (1.378 × 10Nt/m2) can be obtained. The back pressure on the micropump can be as high as 85 cm-H2O (8,610.5 Nt/m2) at the same operation conditions. The micropump is fabricated by soft lithography processes and can be easily integrated with other microfluidic devices. To demonstrate its capability to prevent cross contamination during chemical analysis applications, two micropumps and a V-shape channel are integrated to perform a titration of two chemical solutions, specifically sodium hydroxide (NaOH) and benzoic acid (C6H5COOH). Experimental data show that mixing with a pH value ranging from 2.8 to 12.3 can be successfully titrated. The development of this micropump can be a promising approach for further biomedical and chemical analysis applications.

Keywords

MicrofluidicsMEMSMicropumpNormally closed microvalve

List of symbols

CCD

charge-coupled device

C6H5COOH

benzoic acid

EMV

electromagnetic valve

MEMS

micro-electro-mechanical-system

NaOH

sodium hydroxide

PDMS

polydimethylsiloxane

pH

power of hydrogen ions

SEM

scanning electron microscope

UV

ultraviolet

μ-TAS

micro-total-analysis-system

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.Department of Engineering ScienceNational Cheng Kung UniversityTainanTaiwan
  2. 2.Medical Electronics and Device Technology CenterIndustrial Technology Research InstituteHsinchuTaiwan