Microfluidic patterning of nanoparticle monolayers

Chen, Zhe; Zhao, Yu; Wang, Wei; Li, Zhihong

doi:10.1007/s10404-009-0420-y

Cited by 4 publications

(7 citation statements)

References 21 publications

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“…[30] This good mixing effect is gained within 19 mm, which is better than the channel with pillar obstructions in a long distance of nearly 50 mm. [25] Although some of the passive micromixers had high mixing efficiency, [18,19] the fabrication process was quite complicated. Hence, considering both mixing efficiency and fabrication process, our new design has a good future for applications in bioassays and chemical synthesis.…”

Section: Resultsmentioning

confidence: 99%

“…Observing the changes of color or intensity of various indicators is one of the most commonly used methods to evaluate the mixing effect. [25,30] It is well known that phenolphthalein changes its color from colorless to red in alkaline solution. This phenomenon was utilized to evaluate the mixing efficiency of our designed structure for solutions with high diffusion coefficients.…”

Section: Mixing Measurements and Normalizing Methodsmentioning

confidence: 99%

“…Colorless pure water and a red water solution containing 0.05 M phenolphthalein (Xilong Chemicals, China) and 0.3 M NaOH (Xilong Chemicals, China) were injected into the main channel from two inlets using disposable plastic microbore tubes, with the same flow rate using two syringe pumps (Aladdin World Precision Instrument, Germany). [25,26] Hb solution (Sigma, USA) in PBS buffer (0.2 M, pH 7.4) and pure PBS solution were injected into the chip from two inlets in the same way. [8] The color changes across the main channel were measured from the images taken by an inverted microscope equipped with a digital camera (Yongheng Optical Equipment Manufacture Co., Ltd, China).…”

Section: Mixing Measurements and Normalizing Methodsmentioning

confidence: 99%

“…[15] Although the aforementioned examples obtained good mixing effect of fluids, external energy is required in all of them, which may be harmful to biological reagents. Fortunately, this problem can be solved by passive mixers, because passive mixers are designed by channels with different geometry (chaotic method [18][19][20][21][22][23] ) or special types of baffles embedded in the main channel (split-and-rejoin strategy [24][25][26][27][28][29][30][31][32] ) with no other external energy. Chaotic method is widely used for micromixing with special structures modified on the channel wall.…”

Section: Introductionmentioning

confidence: 99%

“…[20,21,23] Detailed investigations of an obstruction-pair mixer were presented with numerical and experimental analysis, [18] which is also a variation of staggered herringbone structure. In the other aspect, split-and-join approach is also a commonly used strategy to enhance mixing in passive mixers, in which many types of baffles were embedded into the main channel, such as cylindrical obstructions, [24,25,32] diamond obstructions, [24,26,31] triangle baffles, [24] elliptic-shape barriers, [29] J-shape baffles [30] and other special structures. [19,24,27,28] Most of them are complicated and difficult to fabricate.…”

Section: Introductionmentioning

confidence: 99%

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Micromixing enhancement in a novel passive mixer with symmetrical cylindrical grooves

Wang

Han

2015

Asia-Pacific J Chem Eng

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A passive micromixer with symmetrical cylindrical grooves along the channel was designed, fabricated and characterized. Systematic numerical simulations of mixing with Re ranging from 1.0 to 500 predict the optimized parameters and the mixing enhancement. The optimized depth of the cylindrical grooves is 100 µm. The experimental results have also confirmed the improvement of the mixing effect. Considering pressure drop and mixing enhancement, Re values of 10 and 100 are suitable for mixing of liquids with diffusion coefficients of 10−9 and 6 × 10−11 m2/s, respectively. The percentage of mixing of this micromixer is 2.22‐fold better than that of common Y‐mixer with Re of 10 at the distance of 19 mm from the meeting point of two fluids with the diffusion coefficient of 10−9 m2/s; similarly, the percentage of mixing of the new design is 2.18 times better than that of common Y‐mixer with Re of 100 at the distance of 19 mm from the meeting point of two fluids with the diffusion coefficient of 6 × 10−11 m2/s. This easy fabricated micromixer can be utilized for biological reactions and analytical assays. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 99%

Section: Mixing Measurements and Normalizing Methodsmentioning

confidence: 99%

Section: Mixing Measurements and Normalizing Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Micromixing enhancement in a novel passive mixer with symmetrical cylindrical grooves

Wang

Han

2015

Asia-Pacific J Chem Eng

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Silicones for Microfluidic Systems

Kowalewska

Nowacka

2014

Concise Encyclopedia of High Performance Silicones

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Probing Lateral Charge Transport in Single Molecule Layers: How Charge is Transported Over Long Distances in Fullerene Self‐Assembled Monolayers

Dubacheva

Devynck

Raffy

et al. 2013

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Self-assembled monolayers (SAMs) are good candidates for electronic molecular devices as they are compatible with fl exible substrates, show reliable fi lm-forming behavior, fi t well with the miniaturization concept and can be easily functionalized by changing the constituent molecular components. [ 1 ] Most studies on the electrical properties of SAMs have focused on the conduction along the molecular axis [ 2 ] even though this is a minor aspect of the electrical transport in SAMs as they are inherently intended to operate through lateral charge transport which instead depends strongly on intermolecular packing. [ 3 ] Several approaches, [ 4 ] some of which are outlined in Figure 1 , have been proposed to study the lateral electrical transport in SAMs. Field-effect transistor devices in which the semiconductor channel is a single sheet of molecules formed on the gate dielectric (SAMFETs, Figure 1 a) are the most common approach and allow the charge carrier mobility to be extracted from the fi eld-dependence of the source-drain current. [ 5 ] In the case of SAMs formed on conductive substrates, the dependence of the domain height on the size of isolated molecular islands as measured by scanning tunneling microscopy (STM, Figure 1 b) provides an indirect assay of intermolecular charge transport between neighboring molecules. [ 6 ] However, these techniques disagree widely on the magnitude and mechanism of charge transport in monolayers, which can range from very high mobility through ballistic charge transport [ 5 ] to low-to-moderate mobility via percolation. [ 7 ] To date, direct probing of the conductivity of a single molecule layer has not been possible due to the diffi culty of achieving good electrical contact without damaging the monolayer and the low currents that are expected in the absence of a fi eld-effect. In this respect, conducting atomic force microscopy (C-AFM, Figure 1 c), is particularly well adapted as the combination of AFM imaging and C-AFM electrical characterization enables separate (in contrast to STM) and simultaneous (in contrast to SAMFETs) investigation of the structure and function of molecular assemblies. [ 2c ] In addition, C-AFM can be used to measure samples with widely varying conductance, while positioning an electrical probe with nanometer scale precision and controlled force, [ 8 ] thus enabling the channel length to be varied in a step-wise fashion down to tens of nanometers. [ 2c ] Several groups have successfully used this technique to study electrical transport in surface-confi ned nanostructures such as semiconductor crystals, [ 8,9 ] DNA molecules, [ 10 ] inorganic [ 11 ] and organic [ 12 ] nanowires, and carbon nanotubes. [ 13 ] However, initial attempts to measure the lateral transport in SAMs using C-AFM were unsuccessful and the weak currents observed were attributed to tunneling between the tip and the fi xed electrode. [ 14 ] Achieving good contact between a monolayer and a metal electrode is critical for electrical measurements. The evaporation of a ...

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Microfluidic patterning of nanoparticle monolayers

Cited by 4 publications

References 21 publications

Micromixing enhancement in a novel passive mixer with symmetrical cylindrical grooves

Micromixing enhancement in a novel passive mixer with symmetrical cylindrical grooves

Silicones for Microfluidic Systems

Probing Lateral Charge Transport in Single Molecule Layers: How Charge is Transported Over Long Distances in Fullerene Self‐Assembled Monolayers

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