Stability of Polycarbonate and Polystyrene Surfaces after Hydrophilization with High Intensity Oxygen RF Plasma

Larsson, Anders; Dérand, Helene

doi:10.1006/jcis.2001.8032

Cited by 67 publications

(67 citation statements)

References 19 publications

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“…The burst frequency is largely dependent on the surface energy of the material, which can vary depending on the surface treatment conditions used and the dynamic time dependency of the contact angle. For example, oxygen-plasma-treated polycarbonate can undergo surface treatment degradation \30 days after treatment (Larsson and Dérand 2002). It remains difficult to robustly characterize capillary valve burst frequencies to define operation parameters when using hydrophilic materials.…”

Section: Serial Valving On Centrifugal Microfluidic Platformsmentioning

confidence: 99%

“…The main drawback of siphoning on the CD is the requirement of a hydrophilic channel, which is most often obtained by surface treatment of an originally hydrophobic surface. Surface treatments add complexity to characterization of fluidic behavior, as they can show a dynamic behavior over time as surface energy decreases (Beaulieu et al 2009;Larsson and Dérand 2002). For example, polycarbonate can be exposed to oxygen-plasma to create a hydrophilic surface.…”

mentioning

confidence: 99%

“…For example, polycarbonate can be exposed to oxygen-plasma to create a hydrophilic surface. However, this surface treatment methodology is time dependent, and treatments can degrade over a time scale of days (Larsson and Dérand 2002). Fig.…”

mentioning

confidence: 99%

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Serial siphon valving for centrifugal microfluidic platforms

Siegrist

Gorkin

Clime

et al. 2009

Microfluid Nanofluid

130

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Today, the focus in microfluidic platforms for diagnostics is on the integration of several analysis steps toward sample-to-answer systems. One of the main challenges to integration is the requirement for serial valving to allow the sequential release of fluids in a temporally and spatially controlled manner. The advantages offered by centrifugal microfluidic platforms make them excellent candidates for integration of biological analysis steps, yet they are limited by the lack of robust serial valving technologies. This is especially true for the majority of centrifugal microfluidic devices that rely on hydrophilic surfaces, where few passive serial valving techniques function reliably. Building on the useful functionality of centrifugal microfluidic siphoning previously shown, a novel serial siphon valve is introduced that relies on multiple, inline siphons to provide for a better controlled, sequential release of fluids. The introduction of this novel concept is followed by an analytical analysis of the device.Proof-of-concept is also demonstrated, and examples are provided to illustrate the range of functionality of the serial siphon valve. The serial siphon is shown to be robust and reproducible, with variability caused by the dependence on contact angle, rotation velocity, and fluidic properties (viz., surface tension) significantly reduced compared to current microfluidic, centrifugal serial valving technologies.

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Section: Serial Valving On Centrifugal Microfluidic Platformsmentioning

confidence: 99%

mentioning

confidence: 99%

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Serial siphon valving for centrifugal microfluidic platforms

Siegrist

Gorkin

Clime

et al. 2009

Microfluid Nanofluid

130

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“…Several techniques are available to render a hydrophobic surface hydrophilic, including the deposition of a hydrophilic coating on the hydrophobic surface and the modification of the hydrophobic surface through chemical or physical surface treatments Kido et al 2007). A severe limitation comes about in the latter case, because surface treatments such as the exposure of polycarbonate to oxygen (O 2 ) plasma are not permanent and result in a change of the fluidic behavior of the system over time (Larsson and Dérand 2002;Beaulieu et al 2009). Typical treatments do degrade in a matter of days, thereby hindering the intended functionality of the CD (Larsson and Dérand 2002).…”

Section: Introductionmentioning

confidence: 99%

“…A severe limitation comes about in the latter case, because surface treatments such as the exposure of polycarbonate to oxygen (O 2 ) plasma are not permanent and result in a change of the fluidic behavior of the system over time (Larsson and Dérand 2002;Beaulieu et al 2009). Typical treatments do degrade in a matter of days, thereby hindering the intended functionality of the CD (Larsson and Dérand 2002).…”

Section: Introductionmentioning

confidence: 99%

Pneumatic pumping in centrifugal microfluidic platforms

Gorkin

Clime

Madou

et al. 2010

Microfluid Nanofluid

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Centrifugal microfluidics has emerged as a unique approach to the development of integrated total analysis systems for medical diagnostics. However, despite its many advantages, the platform has a size limitation due to the centripetal pumping mechanism in which fluids can only be moved from the center of the disc to the rim. This limits the footprint of the microfluidic network to one radius of the disc, and this in turn limits the amount of space available to embed complex assays. In order to overcome this space limitation problem, we are developing new techniques to pump fluids back toward the center of the disc as to allow greater path lengths for the fluidic network. This study presents a novel pumping mechanism for centrifugal microfluidics utilizing a combination of centrifugation and pneumatic compression. Pneumatic energy is stored during high-speed centrifugation with sample fluids trapping then compressing air in specially designed chambers. The accumulated pneumatic energy is released by spinning down, which expands the trapped air and thus pumps liquids back toward the center of the CD. This newly developed method overcomes current limitations of centripetal pumping avoiding external manipulation or surface treatments. In this article, we explore the design of appropriate chambers to induce pneumatic pumping and analytically describe the mechanics behind the pumping action. For proof of principle, we have applied pneumatic pumping to siphon priming.

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Chemical Protection of Polycarbonate Surfaces by Atomic Layer Deposition of Alumina with Oxygen Plasma Pretreatment

Park

Bae

Kim

et al. 2016

Adv Materials Inter

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has been proposed, and various coating methods including sol-gel process, physical vapor deposition, and chemical vapor deposition (CVD) have been attempted. [1c,5] The recent progress on atomic layer deposition (ALD) techniques has attracted attention as a potential process to manufacture such polymer-protection ceramic coating films. [6] ALD is capable of producing ceramic and metal thin films at relatively low temperatures. For example, alumina and zinc oxide films can be readily deposited by ALD even at room temperature using volatile and reactive precursors such as trimethylaluminum (TMA) and diethylzinc, respectively. [7] In addition, ALD can be used to fabricate dense and conformal films [8] along complex-shaped contours with high aspect ratios. There have been several reports on coating of trenches, tubes, rods, and particles at the nanoscale using ALD. [9] Due to these characteristics, ALD enables protection coating of polymer films without pinholes, despite the nonflat and irregular surface morphology that might contain pores.Functional groups, such as terminal hydroxyls and carbonyls present at the extremities of the polymeric chain branches or broken chains, are important for the successful ALD growth on polymers, [10] because they provide active sites for the chemisorption of precursors and initial nucleation of the ALD material islands. It is also possible to grow ALD films on certain polymers in the absence of those functional groups, since precursors can react and form solid materials in adsorbed states or even in the gas-phase. [11] However, in this case, there is no chemical binding between the substrate surface and the films, where the ALD layer forms a separated "shell" physically set on the polymer support. For example, ALD films grown on polytetrafluoroethylene (PTFE), whose surface is chemically inert, exhibit poor binding with the substrate and are easily delaminated. [12] It is also well known in PCs that TMA precursors tend to chemisorb poorly on the surface compared to other polymer materials due to the absence of appropriate functional groups. [10a,b] Plasma treatment processes have been used to clean wafers by decomposing organic impurities or to provide functional groups for an improved initiation of the CVD and ALD film growth. [10c,13] Based on this approach, we propose a plasma pretreatment of the PC substrates for the fabrication of high quality ALD This study reports the effect of an O 2 plasma pretreatment of polycarbonate (PC) films for the enhanced integration of Al 2 O 3 films prepared by atomic layer deposition (ALD) on the PC substrate. It is revealed that the plasma treatment produces functional groups on the PC surface, which are essential for the ALD of Al 2 O 3 . Specifically, it is revealed that a significant amount of carbonyl groups, essential for the chemisorption of the precursors and covalent binding with the Al 2 O 3 surface protection layer, are present in the plasma-treated PC surface. To evaluate the chemical resistivity of the PC-ALD alumina film, an...

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Stability of Polycarbonate and Polystyrene Surfaces after Hydrophilization with High Intensity Oxygen RF Plasma

Cited by 67 publications

References 19 publications

Serial siphon valving for centrifugal microfluidic platforms

Serial siphon valving for centrifugal microfluidic platforms

Pneumatic pumping in centrifugal microfluidic platforms

Chemical Protection of Polycarbonate Surfaces by Atomic Layer Deposition of Alumina with Oxygen Plasma Pretreatment

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