Continuously variable mixing-ratio micromixer with elastomer valves

• Published in: Journal of micromechanics and microengineering 2005-10, Vol.15 (10), p.1885-1893
• Main Authors: Tan, Christabel K L, Tracey, Mark C, Davis, John B, Johnston, Ian D
• Format: Article
• Language: English
• Subjects: Applied fluid mechanics; Applied sciences; Exact sciences and technology; Fluid dynamics; Fluidics; Fundamental areas of phenomenology (including applications); Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Machine components; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Micromechanical devices and systems; Physics; Precision engineering, watch making; Seals and gaskets
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/0960-1317/15/10/014

We report a self-contained microfluidic alternate flow injection mixer (AFIM) employing piezoelectrically actuated, PDMS seal-valves to control injection. AFIMs employ pulsatile injection of liquids to enhance interface surface generation. By allowing control of pulse-volume proportionality by variation of the duty-cycle of the valve control signals, continuously variable ratio mixing is achieved without external fluid control components. Mixing is discussed in the context of 'rate of new surface generation', thus allowing comparison with laminating mixer designs. The prototype mixer employs a simple micromould fabrication technique to minimize reversible elastomer valve-seal adhesion and hence allow correct valve operation. The resulting device has been characterized over a range of mixing ratios.