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Chwa, Sang Ok; Kim, K. H.

doi:10.1023/a:1006626124472

Cited by 12 publications

(6 citation statements)

References 9 publications

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“…On the other hand, it is expected that the robustness of the roughness generated by our process, which originates from the internal morphology of cellulosic fibers, should be improved relative to that of structures created by traditional polymer grafting or nanoparticle deposition. To confirm this hypothesis, the robustness of the surface was tested with a standardized scotch tape test (ASTM). , The result was damage to the paper substrate, with a layer of fibers adhering to the scotch tape, Apparently, adhesion failure occurred at fiber−fiber interfaces rather than fiber−PFE interfaces, which demonstrates that the PFE film has excellent adhesive bonding to the fibers. This observation is consistent with the fact that cellulose has numerous −OH moieties which serve as reaction sites for covalent bonding to a cross-linked PFE film.…”

Section: Resultsmentioning

confidence: 99%

“…To confirm this hypothesis, the robustness of the surface was tested with a standardized scotch tape test (ASTM). 57,58 The result was damage to the paper substrate, with a layer of fibers adhering to the scotch tape, Apparently, adhesion failure occurred at fiber-fiber interfaces rather than fiber-PFE interfaces, which demonstrates that the PFE film has excellent adhesive bonding to the fibers. This observation is consistent with the fact that cellulose has numerous -OH moieties which serve as reaction sites for covalent bonding to a cross-linked PFE film.…”

Section: Robustness and Stability Of The Superhydrophobic Paper Subst...mentioning

confidence: 99%

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Fabrication of “Roll-off” and “Sticky” Superhydrophobic Cellulose Surfaces via Plasma Processing

2008

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Most of the artificial superhydrophobic surfaces that have been fabricated to date are not biodegradable, renewable, or mechanically flexible and are often expensive, which limits their potential applications. In contrast, cellulose, a biodegradable, renewable, flexible, inexpensive, biopolymer which is abundantly present in nature, satisfies all the above requirements, but it is not superhydrophobic. Superhydrophobicity on cellulose paper was obtained by domain-selective etching of amorphous portions of the cellulose in an oxygen plasma and subsequently coating the etched surface with a thin fluorocarbon film deposited via plasma-enhanced chemical vapor deposition using pentafluoroethane as a precursor. Variation of plasma treatment yielded two types of superhydrophobicity : "roll-off" (contact angle (CA), 166.7 degrees +/- 0.9 degrees ; CA hysteresis, 3.4 degrees +/- 0.1 degrees ) and "sticky" (CA, 144.8 degrees +/- 5.7 degrees ; CA hysteresis, 79.1 degrees +/- 15.8 degrees ) near superhydrophobicity. The nanometer scale roughness obtained by delineating the internal roughness of each fiber and the micrometer scale roughness which is inherent to a cellulose paper surface are robust when compared to roughened structures created by traditional polymer grafting, nanoparticle deposition, or other artificial means.

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Section: Resultsmentioning

confidence: 99%

Section: Robustness and Stability Of The Superhydrophobic Paper Subst...mentioning

confidence: 99%

Fabrication of “Roll-off” and “Sticky” Superhydrophobic Cellulose Surfaces via Plasma Processing

2008

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“…Films of Cu 3 N have been successfully produced by sputtering methods using copper and nitrogen as source materials. 1,[3][4][5]10,[15][16][17] Other used Cu 3 N deposition methods are molecular beam epitaxy ͑MBE͒ 6 and ablation of copper in a nitrogen ambient. 18 Cu 3 N films have also been grown by CVD.…”

mentioning

confidence: 99%

Growth of Copper(I) Nitride by ALD Using Copper(II) Hexafluoroacetylacetonate, Water, and Ammonia as Precursors

Törndahl

Ottosson

Carlsson

2006

J. Electrochem. Soc.

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Films of copper͑I͒ nitride were deposited by atomic layer deposition ͑ALD͒ using copper͑II͒ hexafluoroacetylacetonate, water, and ammonia as precursors. Introduction of a water pulse in the ALD cycle was found to be crucial for initiating film growth on both amorphous SiO 2 and single-crystalline ␣-Al 2 O 3 ͑001͒ substrates. The water pulses generated an oxidic copper monolayer, which in a subsequent ammonia pulse was converted to the nitride. The films have been grown in the temperature range from 210 to 302°C. Phase pure films of Cu 3 N were obtained up to 265°C. At higher deposition temperatures such as 283°C, phase mixtures of Cu 3 N and Cu were obtained. For temperatures above 302°C films of only Cu were grown. Film growth rate was the same on the two different substrates. The films were randomly oriented on SiO 2 . Completely intact films were obtained at a thickness of 20 nm. The optical bandgap of the films was measured to be 1.6 eV.

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“…An adhesion test according to ASTM D3359 was performed to assess the adhesion of the anodic alumina films to the glass substrate. 15 A piece of pressure-sensitive tape was firmly applied to the film, then pulled away. Before the ion-drift process, most of aluminum oxide layer was peeled off from the substrate, indicating poor adhesion between the film and substrate.…”

Section: Resultsmentioning

confidence: 99%

Nanoporous Anodic Alumina Film on Glass: Improving Transparency by an Ion-Drift Process

Park

Lee

Cho

et al. 2005

Electrochem. Solid-State Lett.

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A novel method for increasing the transparency of an anodic aluminum oxide film on glass is demonstrated. The residual aluminum layer, which limits the transparency of the porous aluminum oxide film, was fully converted to its oxide by the ion-drift process. The transmittance of the film was improved more than 20% over the visible-near infrared range and was similar to that of a glass substrate. This ion-drift process also improved the adhesion of the anodic alumina film to the glass substrate.Nanoporous anodic aluminum oxide films are of great interest in various applications because of their stability and unique structural and optical properties. 1,2 As their applications grow, specific requirements for the preparation of anodic alumina film are increased. For example, a transparent porous anodic alumina film on glass is highly desired in optical and optoelectronic devices.The anodization of an aluminum film on an insulating substrate always leaves an unoxidized aluminum metal and results in a semitransparent ͑dark colored͒ anodic alumina film. Miney et al. estimate the thickness of the unoxidized aluminum layer to be ϳ1.2 nm from an ellipsometric study. 3 Although the remaining aluminum layer is very thin, the transmittance of the anodic alumina film rarely exceeds 60%, as aluminum is one of the most optically dense metals.Nearly all the previous work on complete anodization of aluminum films on insulating substrates was done by inserting a conducting medium between the substrate and the aluminum layer. Very thin layers of valve metals, such as titanium, 4 niobium, 5 and tantalum, 6,7 were introduced for this purpose. However, this produces a bulge of valve metal oxide and leaves the unoxidized layer that also reduces the transmittance. Chu et al. utilizes a transparent indium-tin oxide ͑ITO͒ layer as a conducting medium and the transmittance of the anodic alumina film was nearly equivalent to that of ITO glass. 8 It was found to be very difficult to prepare a uniform, large area anodic alumina film, however. Temperature, electric field, and the thickness of aluminum and conducting films must be uniform over entire substrate and the anodization process must be critically controlled. Otherwise, nonuniform anodization will be obtained. Also, gas evolution and sparking destroy the alumina film as the anodization reaches the Al-conducting medium interface. In addition, the adhesion between the alumina film and substrate is poor if an aluminum layer on a conducting medium is anodized. 9 This lack of adhesion may be beneficial for some purposes such as a nano-pattern transfer and preparation of free standing films, but it is highly undesirable in most applications.In other contexts, anodic bonding is widely used in microsystem technology to join glass and silicon. 10 The basic mechanism is the thermal activation of alkali and oxygen ions and their drift in the electric field applied during bonding. 11,12 This generates a high electric field within the depletion region and forms homogeneous and reliable bonds through...

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Untitled

Cited by 12 publications

References 9 publications

Fabrication of “Roll-off” and “Sticky” Superhydrophobic Cellulose Surfaces via Plasma Processing

Fabrication of “Roll-off” and “Sticky” Superhydrophobic Cellulose Surfaces via Plasma Processing

Growth of Copper(I) Nitride by ALD Using Copper(II) Hexafluoroacetylacetonate, Water, and Ammonia as Precursors

Nanoporous Anodic Alumina Film on Glass: Improving Transparency by an Ion-Drift Process

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