Diffuser Micropump Structured with Extremely Flexible Diaphragm of 2-µm-thick Polyimide Film

Abstract

A miniaturized diffuser/nozzle micropump with extremely thin (only 2.1 µm in thickness) polyimide (PI) membranes was fabricated on a 60-µm-thick Si wafer using simple photolithography processes. The diameter of the diaphragm was 2 mm, and the chamber depth was 60 µm. The micropump was functioned by deforming the membranes with alternating air pressure. The ethanol flow rate of the micropump was over 400 nl/min at 2.5 Hz with an actuated pressure of 5 kPa. The measured flow rate was relatively higher than those of previously reported micropumps with a similar chamber volume owing to the large deflection (over 40 µm) of the PI membrane. The micropump processing issues of plasma induced damage to the PI membrane during Si chamber etching and the behaviors of the static and dynamic deflections of the PI membrane was also discussed. On the basis of the advantages of photolithography processes and the good performance of the micropump, it is expected that the micropump can be fabricated on silicon integrated circuit chips.

A review on micropumps from the viewpoint of volumetric power density

“…From the overview of latest articles, there can be seen comparatively many MEMS based silicon type (Dau, et al, 2009, Lemke, et al, 2011, Spieth, et al, 2012, Yoon, et al, 2007 , polymer membrane type (Fang and Tan, 2010, Doll, et al, 2007, Kim, et al, 2008, Liu, et al, 2011, Ni, et al, 2010 , piezo-element type (Geipel, et al, 2008, Herz, et al, 2010, Izzo, et al, 2007, Kang and Auner, 2011, De Lima, et al, 2009, Ogawa, et al, 2009, Tseng, et al, 2013, Wei, et al, 2014 and peristaltic type (Koch, et al, 2009, Cole, et al, 2011, Chia, et al, 2011, Lee, et al, 2012, Nakahara, et al, 2013 micropumps. Nowadays, it must be obvious that MEMS technology is a most powerful tool for realizing micro devices, and the process is often employed to fabricate devices in many researches.…”

Profile Characterization and Temperature Effect on the Wettability of Microstructured Surfaces

“…Moreover, surface wettability at a high temperature (30˚C to 90˚C) is important in industrial processes [16] such as water transportation and metal processing [17]. Recently, several advances have been made such as the following: superhydrophobic surface hot water repellent [18]; the nucleate boiling based on the lyophilic micro-structured surface leads high critical heat flux [19]; the fabrication of wetting-controllable thermally responsive materials [20] [21]; wetting transition on hydrophobic microstructures surface during evaporation [22] [23] [24]; low temperature heat exchange on hydrophobic surfaces [25]. The theory and applications of droplet wetting behavior on hot surfaces are very important in the solid-liquid heat transfer system [26].…”

A Ferrofluidic Magnetic Micropump for Variable-Flow-Rate Applications

“…The literature contains many proposals for micropumping schemes, including acoustic-wave-based, rotary, piezoelectric, thermopneumatic, electrostatic, electromagnetic and ferrofluidic. [31][32][33][34][35][36][37][38][39][40][41][42] Of these various methods, ferrofluidic actuators are particularly attractive due to their extended working range, rapid response time and simple structure. 1stergaard et al 43) proposed a ferromagnetic actuator for the automation of clinical chemistry comprising three magnets (alignment, launch, and compensation) individually driven by a computer.…”