Particle velocity field measurements in a near-wall flow using evanescent wave illumination

Zettner, Claudia Margaret; Yoda, Minami

doi:10.1007/s00348-002-0541-5

Cited by 143 publications

(91 citation statements)

References 12 publications

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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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“…7͑b͒ and 7͑c͒ ͑in which the variation in each histograms can be explained by the particle polydispersity͒ indicate that the evanescent-wave illuminations at z = 0 on the ridges and on the valleys are indeed similar, as expected in our discussion on the optical effects of the surface structures. Note that while previous researchers have tried calibrating their evanescent-wave intensity distribution ͑along the z-axis͒ by using precise z-axis displacement of a particle in the evanescent wave, 11,16 this calibration technique cannot be applied for our samples. This is because to operate this technique, the lower wall has to be disassembled from the complete microchannel and then laid directly on the TIRFM setup.…”

Section: ͑6͒mentioning

confidence: 99%

“…14 When the liquid is seeded with nanometric-scale fluorescent particles, the displacement of the particles can then be imaged by TIRFM recordings and further analyzed to deduce the fluid velocity distributions. 11,12 This method is particularly advantageous because the penetration depth is in the order of ϳ100 nm, such that the evanescentwave illumination selectively probes only the near-wall flow properties close to the surface under study. This method has allowed previous researchers to characterize the pressure driven as well as electro-osmotic near-wall velocities, both at hydrophobic and hydrophilic surfaces.…”

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confidence: 99%

Nanoparticle image velocimetry at topologically structured surfaces

et al. 2009

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Nanoparticle image velocimetry ͑nano-PIV͒, based on total internal reflection fluorescent microscopy, is very useful to investigate fluid flows within ϳ100 nm from a surface; but so far it has only been applied to flow over smooth surfaces. Here we show that it can also be applied to flow over a topologically structured surface, provided that the surface structures can be carefully configured not to disrupt the evanescent-wave illumination. We apply nano-PIV to quantify the flow velocity distribution over a polydimethylsiloxane surface, with a periodic gratinglike structure ͑with 215 nm height and 2 m period͒ fabricated using our customized multilevel lithography method. The measured tracer displacement data are in good agreement with the computed theoretical values. These results demonstrate new possibilities to study the interactions between fluid flow and topologically structured surfaces.

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“…Evanescent wave total internal reflection has been used with nanoPIV (nPIV). [30][31][32][33][34] This method can measure the flow velocity within a distance of 100 nm from the solid wall, and even the velocity distribution near the wall in microchannel. 35 Both mPIV and nPIV use particles whose diameters are of the same order as a nanochannel, and therefore are not suitable in nanofluidics systems since the particles can disturb and block flow and thus are no longer ''passive''.…”

Section: Introductionmentioning

confidence: 99%

A novel far-field nanoscopic velocimetry for nanofluidics

Kuang

Wang

2010

Lab Chip

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For the first time we have been able to measure the flow velocity profile for nanofluidics with a spatial resolution better than 70 nm. Due to the diffraction resolution barrier, traditional optical methods have so far failed in measuring the velocity profile in a nanocapillary or a closed nanochannel without an opened sidewall. A novel optical point measurement method is presented which applies stimulated emission depletion (STED) microscopy to laser induced fluorescence photobleaching anemometer (LIFPA) techniques to measure flow velocity. Herein we demonstrate this far-field nanoscopic velocimetry method by measuring the velocity profile in a nanocapillary with an inner diameter of 360 nm. The closest measuring point to the wall is about 35 nm. This method opens up a new class of functional measuring techniques for nanofluidics and for nanoscale flows from the wall.

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Particle velocity field measurements in a near-wall flow using evanescent wave illumination

Cited by 143 publications

References 12 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

Nanoparticle image velocimetry at topologically structured surfaces

A novel far-field nanoscopic velocimetry for nanofluidics

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