Dynamic Sequential Layer-by-Layer Deposition Method for Fast and Region-Selective Multilayer Thin Film Fabrication

Kim, Hyong Jun; Lee, Kangwon; Kumar, Sameer; J, Kim

doi:10.1021/la0511182

Cited by 57 publications

(43 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Recently, the obstacle-mediated geometry combined with an alternating droplet generation was introduced to conduct a multilayer deposition process . In order to realize the multilayer deposition in the continuous microfluidic framework gives a fast, efficient automated way comparing to conventional batch process (Priest et al 2008;Kim et al 2005). Therefore, it will be necessary to understand relevant physics on the deposition process where the droplets are passing through obstructions in confined microchannels.…”

mentioning

confidence: 99%

Droplet dynamics passing through obstructions in confined microchannel flow

Chung

Lee

Char

et al. 2010

Microfluid Nanofluid

View full text Add to dashboard Cite

Motivated by the previous studies (Lee et al., Lab Chip 10:1160-1166, 2010 Link et al., Phys Rev Lett 92:054503-1-054503-4, 2004), the droplet dynamics passing through obstructions in confined microchannel was explored both numerically and experimentally. The effects of obstruction shape (cylinder and square), droplet size, and capillary number (Ca) on droplet dynamics were investigated. For the size control, due to an obstructioninduced droplet breakup, the cylinder obstruction was found to be advantageous over square type for practical purposes. The thread breakup was attributed to both normal and shear components of velocity gradients near the obstruction, in particular, near the corners of the square. As a result, the square obstruction was considered to generate more non-trivial satellite droplets. The droplet size showed little influence on the droplet dynamics. Considering the wetting process on the cylinder surface, we explored the droplet dynamics passing through two successive cylinder obstructions, where more complicated dynamics was observed depending on Ca (capillary number * viscous force / interface tension), cylinder interval, and droplet size. Here, we propose two requirements for independent wetting on each cylinder: (i) low Ca droplet should be manipulated, and (ii) cylinder interval should be larger than channel width. That is, low Ca droplet could intrude the region between two cylinders if the cylinder interval was far enough, while the droplet could not intrude due to geometric hindrance for close obstructions. In the numerical viewpoint, the proposed requirements were also valid for multi-cylinder obstructions up to 6. In addition, we propose a novel design of array structure of cylinders for a selective wetting, which might be useful to fabricate Janus particles. We hereby prove by both simulation and experiments that the wetting on the obstruction is controllable by changing Ca and cylinder design in the multilayer deposition process.

show abstract

mentioning

confidence: 99%

Droplet dynamics passing through obstructions in confined microchannel flow

Chung

Lee

Char

et al. 2010

Microfluid Nanofluid

View full text Add to dashboard Cite

show abstract

“…Usually, global control over the conformation of adsorbed chains can be performed by adjusting the ionic strength of the solutions to screen electrostatic interactions between charged units [168]. This technique is very versatile and attractive since the region-selective dynamic sequential LbL has been demonstrated with fluidic devices on various substrates [169]. The growing of polypeptide films [170] and blood compatible multilayers [171] has been achieved without using expensive facilities, which indicates a promising future for LbL.…”

Section: Polymer Coating By Physisorptionmentioning

confidence: 99%

Surface treatment and characterization: Perspectives to electrophoresis and lab‐on‐chips

et al. 2006

View full text Add to dashboard Cite

The control and modification of surface state is a major challenge in bioanalytical sciences, and in particular in electrokinetic separation methods, due to the importance of electroosmosis. This topic has gained recently a renewed interest, associated with the development of "lab-on-chips" systems that extend the range of materials in which separation channels are fabricated. The surface science community has developed through the years a large toolbox of characterization tools and surface modification protocols, which is not yet fully exploited in the bioanalytical world. In this paper, we try and present an overview of these tools, in order to stimulate new ideas for improved and more controlled surface treatment strategies for separations in capillaries and microchannels. We briefly describe some physical and chemical aspects of electroosmosis (global and spatially resolved), streaming current, and streaming potential. We also review the main strategies for surface coating, and compare the advantages of physisorption, well-organized thin self-assembled monolayers, or conversely thick polymer "brushes". Examples of existing applications to electrophoresis in microchannel are also given.

show abstract

“…Therefore, it is very meaningful for us to detect the concentration of iodate. So far, several techniques have been developed for the determination of iodate, such as spectrophotometry, high performance liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry, chemiluminescence and amperometry [41][42][43][44][45][46]. Nevertheless, most of these methods need to be performed on specific and costly instrument, which makes tests inconvenient.…”

Section: Introductionmentioning

confidence: 99%