Electroless Deposition and Structuring of Silver Electrodes in Closed Microfluidic Capillaries

Heuck, F.; Staufer, U.

doi:10.1109/jmems.2011.2105254

Cited by 11 publications

(4 citation statements)

References 41 publications

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“…As a disadvantage, this oxidation of Ag or AgCl leads to an altering and the consummation of the electrodes during pumping, and they need to be regenerated by changing the pumping direction. Ag electrodes can be electroless deposited into the capillaries of the SIP [101] and further partially transformed into Ag/AgCl based on an oxidation with ferric chloride (FeCl3). First experiments using polymeric capillaries with 65 μm channels a flow rate of 0.12 nL•s −1 •V −1 was obtained [102].…”

Section: Electro-osmotic Pumpmentioning

confidence: 99%

Scanning Probe Microscope-Based Fluid Dispensing

et al. 2014

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Advances in micro and nano fabrication technologies have enabled fabrication of smaller and more sensitive devices for applications not only in solid-state physics but also in medicine and biology. The demand for devices that can precisely transport material, specifically fluids are continuously increasing. Therefore, integration of various technologies with numerous functionalities in one single device is important. Scanning probe microscope (SPM) is one such device that has evolved from atomic force microscope for imaging to a variety of microscopes by integrating different physical and chemical mechanisms. In this article, we review a particular class of SPM devices that are suited for fluid dispensing. We review their fabrication methods, fluid-pumping mechanisms, real-time monitoring of dispensing, physics of dispensing, and droplet characterization. Some of the examples where these probes have already been applied are also described. Finally, we conclude with an outlook and future scope for these devices where femtolitre or smaller volumes of liquid handling are needed.

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Section: Electro-osmotic Pumpmentioning

confidence: 99%

Scanning Probe Microscope-Based Fluid Dispensing

et al. 2014

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“…[3][4][5] One of the less well explored applications of laminar ow is its use as a patterning technique, here termed laminar ow lithography (LFL) wherein reactive uids (etchants or additive deposition solutions) are restricted to specic regions of a microchannel to perform patterning processes. In the literature, LFL has been implemented to modify the surface structure of a microchannel (using a three-stream ow of HF etchant and water in monolithic glass devices creating cylindrical proles), 6 selectively deposit material into channels (using multi-stream ows with electroless plating solutions), [7][8][9][10] etch single metal layers, 11 and achieve combinations thereof. 12,13 To date, the utility of LFL as a general microfabrication technique for patterning multi-layer multi-electrode geometries remains unexplored.…”

Section: Laminar Ow and Laminar Ow Lithographymentioning

confidence: 99%

Patterning multilayer microfluidic electrochemical devices by maskless laminar flow lithography

Nearingburg

Elias

2014

RSC Adv.

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Laminar flow lithography (LFL) is a fabrication technique that leverages the tendency of multiple fluids flowing in a microfluidic channel to remain confined to distinct parallel streams, enabling the substrate to be selectively etched to form patterned lines. The purpose of this investigation was to evaluate LFL as a fabrication technique for patterning multiple layers of parallel metal electrodes to produce microfluidic electrochemical cells. To understand how channel geometry impacts the location and width of the etched structures, finite element modelling (FEM) was used to simulate the profiles of the diffusive gradients that govern the extent and location of etching. LFL was then employed to fabricate two different electrochemical devices requiring parallel electrodes of different materials. First, a three layer Ag-Au-Ni thin film stack was patterned by LFL, yielding a three electrode device with electrically isolated and independently sized Ag, Au, and Ni electrodes within a cyclic-olefin copolymer (COC) microchannel. Second, a functional alkaline direct methanol fuel cell was fabricated by performing two sequential LFL processes to pattern a bi-metallic Ag-Ni film also deposited in a COC microchannel. The electrical characteristics of these Ag-Ni devices were then evaluated. Ag-Ni fuel cells produced a peak open circuit voltage of 185 mV and a peak power density of 12.0 AE 0.4 mW cm À2 (equivalent to 696 AE 20 mW cm À3 , in terms of chamber volume) while flowing 10 mL min À1 of dilute methanol anolyte and dilute hydrogen peroxide catholyte solutions. Fabrication methods presented in this investigation are applicable to many aspects of microfluidics and can be adapted for other types of microfluidic devices where in situ etching is required.

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“…With seeded growth the silica core is usually functionalized (Jackson and Halas, 2001;Kim et al, 2008;Choma et al, 2011), most commonly with either metal ions 20 such as tin (Choma et al, 2012) or an alkoxysilane terminated by either an amine (Kim et al, 2008;Choma et al, 2011;Brinson et al, 2008) or a thiol group (Heuck and Staufer, 2011). The metal nanoparticles are synthesized separately from the silica spheres, and added after the core particle is functionalized.…”

Section: Introductionmentioning

confidence: 99%

Coating nonfunctionalized silica spheres with a high density of discrete silver nanoparticles

Purdy

Muscat

2016

J Nanopart Res

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Reducing AgNO 3 by glucose at basic pH coated the surface of silica spheres with a high density of hemispherical silver nanoparticles (average diameter 3.2±1 nm). A much lower silver concentration than is standard favored heterogeneous nucleation of silver on the silica surface at the expense of homogeneous nucleation in solution. The slow growth rate of the nuclei promoted the formation of discrete silver particles rather than a continuous shell. Based on scanning electron microscopy and transmission electron microscopy, the surface coverage of silver seed particles was as high as 25% at 10• C without prior functionalization of the silica. The particles were composed of metallic silver based on x-ray photoelectron spectroscopy. There was a sharp increase in the silver surface coverage and decrease in the particle size when the temperature was raised from 5 • C to 10 • C and the amount of silica was decreased from 0.2 to 0.025 V/V%. The size was controlled by the diffusion barrier through the ion shell surrounding the silica spheres and by maintaining reaction conditions where the particles on the surface compete for silver.

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Electroless Deposition and Structuring of Silver Electrodes in Closed Microfluidic Capillaries

Cited by 11 publications

References 41 publications

Scanning Probe Microscope-Based Fluid Dispensing

Scanning Probe Microscope-Based Fluid Dispensing

Patterning multilayer microfluidic electrochemical devices by maskless laminar flow lithography

Coating nonfunctionalized silica spheres with a high density of discrete silver nanoparticles

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