Advances and applications on microfluidic velocimetry techniques

Williams, Stuart J.; Park, Choongbae; Wereley, Steven T.

doi:10.1007/s10404-010-0588-1

Cited by 77 publications

(41 citation statements)

References 145 publications

(188 reference statements)

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“…Fluorescent nano/micro beads are typically used as tracers, and a confocal microscope can be used to deduce the velocity distribution in three dimensions [51][52][53][54][55][56][57][58][59]. Evanescent waves generated by total index reflection of a laser can be used to derive the velocity near the liquid/wall interface, within approximately 50 nm, when they are used as the excitation light for the fluorescent tracer particles [60][61][62][63][64].…”

Section: Introductionmentioning

confidence: 99%

Effects of Micromachining Processes on Electro-Osmotic Flow Mobility of Glass Surfaces

et al. 2013

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Silica glass is frequently used as a device material for micro/nano fluidic devices due to its excellent properties, such as transparency and chemical resistance. Wet etching by hydrofluoric acid and dry etching by neutral loop discharge (NLD) plasma etching are currently used to micromachine glass to form micro/nano fluidic channels. Electro-osmotic flow (EOF) is one of the most effective methods to drive liquids into the channels. EOF mobility is affected by a property of the micromachined glass surfaces, which includes surface roughness that is determined by the manufacturing processes. In this paper, we investigate the effect of micromaching processes on the glass surface topography and the EOF mobility. We prepared glass surfaces by either wet etching or by NLD plasma etching, investigated the surface topography using atomic force microscopy, and attempted to correlate it with EOF generated in the micro-channels of the machined glass. Experiments revealed that the EOF mobility strongly depends on the surface roughness, and therefore upon the fabrication process used. A particularly strong dependency was observed when the surface roughness was on the order of the electric double layer thickness or below. We believe that the correlation described in this paper can be of great help in the design of micro/nano fluidic devices.

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Section: Introductionmentioning

confidence: 99%

Effects of Micromachining Processes on Electro-Osmotic Flow Mobility of Glass Surfaces

et al. 2013

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“…Recent reviews about advanced methods, including some 3D techniques and proper experimental design can be found in and Williams et al (2010). However, the main focus of the paper at hand is to put in a common frame modern imaging methods that can be used for a later 3D reconstruction of the velocity field and compare their benefits and drawbacks.…”

Section: Introduction To Lpivmentioning

confidence: 99%

Particle imaging techniques for volumetric three-component (3D3C) velocity measurements in microfluidics

Cierpka

Kähler

2011

J Vis

131

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The reliable measurement of the 3D3C velocity field in microfluidic devices becomes more and more important for future optimization and developments for lab-on-a-chip applications or point-of-care medical diagnosis systems. In the past years, different particle-based imaging methods, such as confocal scanning microscopy, holography, stereoscopic and tomographic imaging or approaches based on defocused particle images or optical aberrations have been developed and applied successfully to measure velocity fields in microfluidic systems. The benefits and drawbacks of these methods will be discussed in detail as the proper understanding of the measurement principle is essential to select the most appropriate technique for a desired measurement application. Once an imaging method is chosen, the velocity can be estimated by correlation-based methods or tracking approaches. The advantages and disadvantages of both methods and the importance of image preprocessing will also be discussed in detail.

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“…To improve the measurement accuracy, a software filter for particle aggregates was also applied. A standard PIV algorithm (Williams et al 2010) was implemented and applied to determine the flow profiles (v x y ð Þ). 1,000-3,000 image pairs were correlated for each flow profile to achieve high accuracy.…”

Section: Methodsmentioning

confidence: 99%

Transient flow behavior of complex fluids in microfluidic channels

Kleβinger

Wunderlich

Bausch

2013

Microfluid Nanofluid

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The ongoing development of microfluidic devices involves the use of highly complex fluids, even of multiphase systems. Despite the great achievements in the development of numerous applications, there is still a lack in the complete understanding of the underlying physics of the observed macroscopic effects. One prominent example is the flow through benchmark contractions where microand even macroscopic explanations of some of the occurring flow patterns are still missing. Here, we study the development of the flow profiles of shear thinning semidilute polymer solutions in microfluidic planar abrupt contraction geometries. Flow profiles along the narrow channel part are obtained by l-PIV measurements, whereby the pressure drop along the microfluidic channel as well as the local transient viscosities downstream to the orifice are computed. A relaxation process of the flow profiles from an initially parabolic shape to the flattened steady-state flow profile is observed and traced back to the polymer relaxation.

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Advances and applications on microfluidic velocimetry techniques

Cited by 77 publications

References 145 publications

Effects of Micromachining Processes on Electro-Osmotic Flow Mobility of Glass Surfaces

Effects of Micromachining Processes on Electro-Osmotic Flow Mobility of Glass Surfaces

Particle imaging techniques for volumetric three-component (3D3C) velocity measurements in microfluidics

Transient flow behavior of complex fluids in microfluidic channels

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