Influence of Nanotips on the Hydrophilicity of Metallic Nanorod Surfaces

Ye, D.-X.; Lu, Toh‐Ming; Karabacak, Tansel

doi:10.1103/physrevlett.100.256102

Cited by 18 publications

(13 citation statements)

References 26 publications

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“…It was found that the average contact angle of Pt nanorods was about 52 • , as shown in figure 4(a), indicating a hydrophilic surface. This value is comparable with the previously reported contact angle of Pt nanorods [23]. Similarly, for the normal angle deposited flat Teflon thin film, the average contact angle was about 108 • (see figure 4(b)), which indicates a hydrophobic surface, and it is in close agreement with the previously reported values of the contact angle of Teflon films [1,10].…”

Section: Contact Angle Measurements and Modelingsupporting

confidence: 92%

“…Under the Cassie and Baxter assumption, the fluid forms a composite surface with the solid where the water droplet sits upon a composite surface of the solid tops and the air gaps, alternating between a fluid-solid interface and a fluid-vapor interface. Therefore, the Wenzel's model [23,24], which assumes that the fluid completely wets the solid structure, was modified by introducing the fractions f s and f a , which correspond to the area in contact with the liquid and the area in contact with the trapped air beneath the drop, respectively [24]:…”

Section: Contact Angle Measurements and Modelingmentioning

confidence: 99%

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Hydrophobic metallic nanorods with Teflon nanopatches

2009

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Introducing a hydrophobic property to vertically aligned hydrophilic metallic nanorods was investigated experimentally and theoretically. The platinum nanorod arrays were deposited on flat silicon substrates using a sputter glancing angle deposition technique (GLAD). Then a thin layer of Teflon (nanopatch) was partially deposited on the tips of platinum nanorods at a glancing angle of theta(dep) = 85 degrees for different deposition times. Teflon deposition on Pt nanorods at normal incidence (theta(dep) = 0 degrees) was also performed for comparison. Morphology and elemental analysis of Pt/Teflon nanocomposite structures were carried out using scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDAX), respectively. It was found that the GLAD technique is capable of depositing ultrathin isolated Teflon nanostructures on selective regions of nanorod arrays due to the shadowing effect during obliquely incident deposition. Contact angle measurements on nanocomposite Pt nanorods with Teflon nanopatches exhibited contact angle values as high as 138 degrees, indicating a significant increase in the hydrophobicity of originally hydrophilic Pt nanostructures that had an angle of about 52 degrees. The enhanced hydrophobicity of the Pt nanorod/Teflon nanopatch composite is attributed to the presence of nanostructured Teflon coating, which imparted a low surface energy. Surface energy calculations were performed on Pt nanorods, Teflon thin film, and Pt/Teflon composite using the two-liquid method to confirm the contact angle measurements. Furthermore, a new contact angle model utilizing Cassie and Baxter theory for heterogeneous surfaces was developed in order to explain the enhanced hydrophobicity of Pt/Teflon nanorods. According to our model, it is predicted that the solid-liquid interface is mainly at the Teflon tips when the composite nanorods are in contact with water.

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Section: Contact Angle Measurements and Modelingsupporting

confidence: 92%

Section: Contact Angle Measurements and Modelingmentioning

confidence: 99%

Hydrophobic metallic nanorods with Teflon nanopatches

2009

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“…Although it is still a subject of controversy, it seems that a critical factor controlling nanocarpet formation is the penetration of the liquid into the inter-rod space of the 1D nanostructured surfaces. Although the literature on this subject has mainly focused on CNT arrays, its expected impact in biomedical research, superhydrophobicity and microfluidics has fostered the investigation of other systems such as OAD nanorods of Si [572][573][574], functionalized Si [575], SiO 2 [576,577], carbon [485], metal [578] and ZnO [563]. Indeed, the nanocarpet effect has already served to increase the WCA on 1D surfaces [563,573] through the formation of a double or hierarchical roughness.…”

Section: Nanocarpet Effectmentioning

confidence: 97%

Perspectives on oblique angle deposition of thin films: From fundamentals to devices

Barranco

Borrás

González‐Elipe

et al. 2016

Progress in Materials Science

616

436

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a b s t r a c tThe oblique angle configuration has emerged as an invaluable tool for the deposition of nanostructured thin films. This review develops an up to date description of its principles, including the atomistic mechanisms governing film growth and nanostructuration possibilities, as well as a comprehensive description of the applications benefiting from its incorporation in actual devices. In contrast with other reviews on the subject, the electron beam assisted evaporation technique is analyzed along with other methods operating at oblique angles, including, among others, magnetron sputtering and pulsed laser or ion beam-assisted deposition techniques. To account for the existing differences between deposition in vacuum or in the presence of a plasma, mechanistic simulations are critically revised, discussing well-established paradigms such as the tangent or cosine rules, and proposing new models that explain the growth of tilted porous nanostructures. In the second part, we present an extensive description of applications wherein oblique-angle-deposited thin films are of relevance. From there, we proceed by considering the requirements of a large number of functional devices in which these films are currently being utilized (e.g., solar cells, Li batteries, electrochromic glasses, biomaterials, sensors, etc.), and subsequently describe how and why these nanostructured materials meet with these needs.

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“…As a result, individual nickel nanorod grown by our technique is a single crystal with facets, which is similar to the results reported previously. 32,35 The top-view and cross-sectional SEM images of the asprepared nickel nanorod arrays on silicon substrates are displayed in Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

Surface diffusion driven morphological instability in free-standing nickel nanorod arrays

Alrashid

2014

Journal of Applied Physics

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Articles you may be interested inStabilization of the surface morphology of stressed solids using simultaneously applied electric fields and thermal gradientsThe effect of a thermal gradient on the electromigration-driven surface morphological stabilization of an epitaxial thin film on a compliant substrate Temperature threshold for nanorod structuring of metal and oxide films grown by glancing angle deposition Metallic nanostructures are thermodynamically unstable due to the excess of energy of large numbers of surface atoms. Morphological instability, such as Rayleigh breakup, sintering, and coalescence, can be observed at a temperature much lower than the bulk melting point of the metal. We study the morphological and crystalline evolution of well-aligned free-standing nickel nanorod arrays at elevated temperatures up to 600 C. The as-deposited nickel nanorods are faceted with sharp nanotips, which are deformed at annealing temperatures higher than 400 C due to strong surface diffusion. A mud-crack like pattern is formed in the samples annealed above 400 C, leading to the generation of interconnected porous structure. Meanwhile, the X-ray diffraction reveals the recrystallization of nickel nanocrystals when annealed from 300 to 600 C. V C 2014 AIP Publishing LLC. [http://dx.

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Influence of Nanotips on the Hydrophilicity of Metallic Nanorod Surfaces

Cited by 18 publications

References 26 publications

Hydrophobic metallic nanorods with Teflon nanopatches

Hydrophobic metallic nanorods with Teflon nanopatches

Perspectives on oblique angle deposition of thin films: From fundamentals to devices

Surface diffusion driven morphological instability in free-standing nickel nanorod arrays

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