Synthesis of superhydrophobic alumina membrane: Effects of sol–gel coating, steam impingement and water treatment

Ahmad, N.A.; Leo, C.P.; Ahmad, Abdul Latif

doi:10.1016/j.apsusc.2013.07.133

Cited by 40 publications

(11 citation statements)

References 33 publications

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“…It is important to note that the production rate in Figure e was predicted in the basis of a surface immersion area of 1 m 2 . In order to achieve higher production rates (i.e., >1000 m 2 /hour), scaled up immersion facilities and more efficient hydro-thermal treatment methods (i.e., impingement with hot steam) are required Figure f shows the comparison of the production rate and specific energy input for different immersion areas of the Al substrate.…”

Section: Resultsmentioning

confidence: 99%

“…In order to achieve higher production rates (i.e., >1000 m 2 / hour), scaled up immersion facilities and more efficient hydrothermal treatment methods (i.e., impingement with hot steam) are required. 83 Figure 10f shows the comparison of the production rate and specific energy input for different immersion areas of the Al substrate. The Al SHP production rate increases linearly with increasing immersion area.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Fabrication Optimization of Ultra-Scalable Nanostructured Aluminum-Alloy Surfaces

Lin

Rabbi

et al. 2021

ACS Appl. Mater. Interfaces

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Aluminum and its alloys are widely used in various industries. Aluminum plays an important role in heat transfer applications, where enhancing the overall system performance through surface nanostructuring is achieved. Combining optimized nanostructures with a conformal hydrophobic coating leads to superhydrophobicity, which enables coalescence induced droplet jumping, enhanced condensation heat transfer, and delayed frosting. Hence, the development of a rapid, energy-efficient, and highly scalable fabrication method for rendering aluminum superhydrophobic is crucial. Here, we employ a simple, ultrascalable fabrication method to create boehmite nanostructures on aluminum. We systematically explore the influence of fabrication conditions such as water immersion time and immersion temperature, on the created nanostructure morphology and resultant nanostructure length scale. We achieved optimized structures and fabrication procedures for best droplet jumping performance as measured by total manufacturing energy utilization, fabrication time, and total cost. The wettability of the nanostructures was studied using the modified Cassie–Baxter model. To better differentiate performance of the fabricated superhydrophobic surfaces, we quantify the role of the nanostructure morphology to corresponding condensation and antifrosting performance through study of droplet jumping behavior and frost propagation dynamics. The effect of aluminum substrate composition (alloy) on wettability, condensation and antifrosting performance was investigated, providing important directions for proper substrate selection. Our findings indicate that the presence of trace alloying elements play a previously unobserved and important role on wettability, condensation, and frosting behavior via the inclusion of defect sites on the surface that are difficult to remove and act as pinning locations to increase liquid–solid adhesion. Our work provides optimization strategies for the fabrication of ultrascalable aluminum and aluminum alloy superhydrophobic surfaces for a variety of applications.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Fabrication Optimization of Ultra-Scalable Nanostructured Aluminum-Alloy Surfaces

Lin

Rabbi

et al. 2021

ACS Appl. Mater. Interfaces

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“…The latter method has been usually applied to prepare hydrophobic or superhydrophobic surfaces on metal or alloy substrates which are intrinsically hydrophilic. Various methods have been developed, including plasma etching [11,12], anodic oxidization [13,14], chemical vapor deposition [15,16], electrochemical deposition [17,18,19], chemical etching [19,20,21,22,23,24], sol-gel [25,26], laser processing [21,23,27], and so on. Hydrophobic or superhydrophobic surfaces reported have been constructed on metal and alloy substrates, such as Mg [28], Cu [23,27,29], Zn [1,30], Al [1,22,31], and Al alloy [5,32].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Hydrophobic Ni Surface by Chemical Etching

et al. 2019

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Hydrophobic surfaces were successfully fabricated on pure nickel substrates by a one-step chemical etching process with different acidic solutions. The static water contact angle (SCA) of the etched Ni surfaces reached higher than 125°, showing excellent hydrophobicity. The examination of surface chemical compositions implied that there were almost no polar moieties on the surface after chemical etching, except part of the surface was oxidized. After chemical etching, the nickel surfaces became much rough with packed terrace-/crater-/thorn-like clusters. According to the analysis of surface composition and morphology, the hydrophobicity was evidently attributed to the rough microstructures on the etched Ni surface. The best hydrophobicity on Ni surface was produced with the SCAs as high as 140.0° by optimizing the etching time and etchants. The results demonstrate that it is possible to construct hydrophobic surfaces on hydrophilic substrates by tailoring the surface microstructure using a simple chemical etching process without any further hydrophobic modifications by low surface energy materials.

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“…The flowerlike structure originates from the formation of pseudoboehmite nanocrystals at the surface of alumina coatings after immersion in hot or boiling water. Formation of boehmite during hot water treatment of alumina layers dried at room temperature results from hydrolysis of chelated EAcAc to Al atoms present in the film (Ahmad et al 2013). When immersing the porous film obtained after heat treatment at 400 C in hot water, then the flowerlike structures result from dissolution of alumina and the associated precipitation of pseudoboehmite (Yamaguchi et al 2005).…”

Section: Posttreatments Of Coatingsmentioning

confidence: 99%

Alumina Thin Films

Nofz¹

2016

Handbook of Sol-Gel Science and Technology

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This chapter gives an overview over preparation, properties, and applications of alumina thin films. The preparation of polymeric and colloidal alumina sols and their deposition on diverse substrate materials with different geometries are described first. Consideration of properties (surface tension, particle size, viscosity, aging of the sols, and their optimization by using certain additives) is included, too. A description of posttreatments of the coatings, which initiate phase transformations and also determine their microstructure, completes the part on coating preparation. Data on adhesion, thickness, surface roughness, and mechanical, textural as well as optical properties of alumina thin films are provided in a further paragraph. In a third main part, experience concerning possible applications, such as (i) membranes for catalysis, separation, and filtration, (ii) barrier layers against electrochemical and high-temperature corrosion or interdiffusion of ions between different phases, (iii) mechanical protection, (iv) sensor construction, (v) improvement of optical properties, as well as (vi) achieving water repellency, is summarized.

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Synthesis of superhydrophobic alumina membrane: Effects of sol–gel coating, steam impingement and water treatment

Cited by 40 publications

References 33 publications

Fabrication Optimization of Ultra-Scalable Nanostructured Aluminum-Alloy Surfaces

Fabrication Optimization of Ultra-Scalable Nanostructured Aluminum-Alloy Surfaces

Fabrication of Hydrophobic Ni Surface by Chemical Etching

Alumina Thin Films

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