Minori Tanaka, Yo Saeki, Itsuo Hanasaki, Yutaka Kazoe
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引用次数: 0
Abstract
With developments of nanofluidics, understanding the behavior of fluids confined in nanospaces becomes important. Particle tracking is an efficient approach, but in nanospaces, it often suffers from the finite temporal resolution, which causes the Brownian displacement of nanoparticles, and the finite spatial resolution due to the decreased signal-to-noise ratio of nanoparticle images, both of which are factors that can cause artifacts. Therefore, in the present study, we simulated nanoparticle tracking velocimetry based on the particle dynamics given by the Langevin equation to evaluate the artifacts. The results revealed that for measurement of the velocity distribution of pressure-driven flow in a 400 nm nanochannel utilizing 60 nm tracer nanoparticles, high-speed (temporal resolution: Δt ≤ 360 µs) and super-resolution (spatial resolution: Δz ≤ 25 nm) measurement is required for errors less than 10%, while insufficient resolution causes an artifact that results in a flattened velocity distribution compared with the original flow profile. The proposed resolutions were experimentally verified by defocusing nanoparticle tracking velocimetry developed by our group. As the simulation predicted, at longer temporal resolution and larger spatial resolution, the measured nanoparticle velocity distribution in the nanochannel indicated a parabolic flow profile but became flattened because of the artifacts. In contrast, at measurement resolutions within the proposed range, the velocity distribution close to the profile given by the Hagen-Poiseuille equation, which was considered to be the actual flow profile, was successfully obtained. This work provides a guideline for nanoscale flow measurements and will accelerate the understanding of specific transport phenomena in nanospaces.
期刊介绍:
Microfluidics and Nanofluidics is an international peer-reviewed journal that aims to publish papers in all aspects of microfluidics, nanofluidics and lab-on-a-chip science and technology. The objectives of the journal are to (1) provide an overview of the current state of the research and development in microfluidics, nanofluidics and lab-on-a-chip devices, (2) improve the fundamental understanding of microfluidic and nanofluidic phenomena, and (3) discuss applications of microfluidics, nanofluidics and lab-on-a-chip devices. Topics covered in this journal include:
1.000 Fundamental principles of micro- and nanoscale phenomena like,
flow, mass transport and reactions
3.000 Theoretical models and numerical simulation with experimental and/or analytical proof
4.000 Novel measurement & characterization technologies
5.000 Devices (actuators and sensors)
6.000 New unit-operations for dedicated microfluidic platforms
7.000 Lab-on-a-Chip applications
8.000 Microfabrication technologies and materials
Please note, Microfluidics and Nanofluidics does not publish manuscripts studying pure microscale heat transfer since there are many journals that cover this field of research (Journal of Heat Transfer, Journal of Heat and Mass Transfer, Journal of Heat and Fluid Flow, etc.).