Print-and-Peel Fabricated Passive Micromixers

Abstract

Advection driven mixing is essential for microfluidics and poses challenges to the design of microdevices. Force transducers or complex channel configurations provide means for, respectively, active or passive disrupting of laminar flows and for homogenizing the composing fluids. Print-and-peel (PAP) is a nonlithographic fabrication technique that involves direct printing of masters for molding polymer components of microdevices. PAP, hence, allows for facile and expedient preparation of microfluidic devices, without requiring access to specialized microfabrication facilities. We utilized PAP for fabrication of microfluidic devices capable of turning, expanding, and contracting microflows. We examined the mixing capabilities of these devices under flow conditions of small Reynolds numbers (0.2-20) and large Peclet numbers (260-26 000), under which advection is the dominant mode of mass transfer. We focused on mixing channels with arched shapes and examined the dependence of the mixing performance on the turns and the expansions along the direction of the microflows. Three-dimensional expansion and contraction, along with an increase in the modes of twisting of the laminar currents, improved the quality of mixing. The simplicity in the described fabrication of the investigated passive micromixers makes PAP an attractive alternative for expedient device prototyping.

Enhancing mixing at a very low Reynolds number by a heaving square cylinder

“…Due to this, the characteristic diffusion timet d along the width of the device (transverseŷ-direction) can be estimated as^=t H D / d 2 , which will be around some orders of magnitude larger than the diffusion time along the depth (ẑ -direction) of the mixing device. Therefore, the mixing in depth takes place much quicker than across the device, being the mixing process limited by the mixing along the channel width (Thomas et al, 2009). This fact reinforces the idea of studying a 2D geometry.…”

Dependence of the quality of adhesion between poly(dimethylsiloxane) and glass surfaces on the composition of the oxidizing plasma

“…Low reagent and power consumption, cost-efficient fabrication, and relatively short operating time periods are some of the key advantages of microfluidic devices (lFDs) (Dittrich and Manz 2006;Whitesides 2006;Thomas et al 2010b). PDMS is a widely used material for fabricating lFDs (Gong and Wen 2009;Zhou et al 2010;Vullev et al 2006; Thomas et al 2010a). Despite its shortcomings, such as porosity (Li et al 2009;Mehta et al 2009;Chueh et al 2007;Shin et al 2003) and susceptibility to a broad range of organic solvents (Lee et al 2003), PDMS is biocompatible (Belanger and Marois 2001;Zhuang et al 2007) and allows for expedient and facile reproduction of features with nanometer precision that are essential for lFDs (Gates 2005;Cong and Pan 2008).…”

Solid-ink-based print-and-peel method for microfluidic fabrication: a revisit

“…Two types of office-grade printers have been used for the PAP method: laser printer [2][3][4][5] and solid-ink printer [6][7][8]. Although laser printers can produce microfluidic molds based on the PAP method, solid-ink printers have an advantage that their solid ink can be printed on nearly any media [9].…”

“…Despite promising results, however, Kaigala et al [6] and following studies [7,8] did not provide rigorous numerical data on the height and surface roughness of solid-inkbased microfluidic mold features, which is critical for other researchers to adopt the method. Therefore, this paper aims to further characterize the PAP method with solid-ink printing and to showcase applications of the method.…”