Why ionizing radiation enhances surface wettability

Seshadri, Arunkumar; Forrest, Eric; Shirvan, Koroush

doi:10.1016/j.apsusc.2020.145935

Cited by 16 publications

(17 citation statements)

References 100 publications

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“… 2 , 15 Moreover, a similar transition has been observed on surfaces oxidized by oxygen plasma treatment, 28 reactive magnetron sputtering, 29 and even ionizing (gamma) radiation. 30 All of this clearly indicates that the mechanisms of the wettability transition after surface oxidation should be universal and should not characteristically depend on a specific metal, metal alloy or even the processing approach and fabrication parameters, as already pointed out by Boinovich et al 18 …”

Section: Influence Of the Low-temperature Annealing On The Wettabilitmentioning

confidence: 74%

Comment on “Bioinspired Reversible Switch between Underwater Superoleophobicity/Superaerophobicity and Oleophilicity/Aerophilicity and Improved Antireflective Property on the Nanosecond Laser-Ablated Superhydrophobic Titanium Surfaces”

Gregorčič

2020

ACS Appl. Mater. Interfaces

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Laser-textured surfaces enabling reversible wettability switching and improved optical properties are gaining importance in cutting-edge applications, including self-cleaning interfaces, tunable optical lenses, microfluidics, and lab-on-chip systems. Fabrication of such surfaces by combining nanosecond-laser texturing and low-temperature annealing of titanium Ti-6Al-4V alloy was demonstrated by Lian et al. in ACS Appl. Mater. Inter . 2020 , 12 (5), 6573–6580. However, it is difficult to agree with (i) their contradictory explanation of the wettability transition due to low-temperature annealing and (ii) their theoretical description of the optical behavior of the laser-textured titanium surface. This comment provides an alternative view—supported by both experimental results and theoretical investigation—on how the results by Lian et al. could be interpreted more correctly. The annealing experiments clarify that controlled contamination is crucial in obtaining consistent surface wettability alterations after low-temperature annealing. Annealing of laser-textured titanium at 100 °C in contaminated and contaminant-free furnaces leads to completely different wettability transitions. Analysis of the surface chemistry by XPS and ToF-SIMS reveals that (usually overlooked) contamination with hydrophobic polydimethylsiloxane (PDMS) may arise from the silicone components of the furnace. In this case, a homogeneous thin PDMS film over the entire surface results in water repellency (contact angle of 161° and roll-off angle of 15°). In contrast, annealing under the same conditions but in a contaminant-free furnace preserves the initial superhydrophilicity, whereas the annealing at 350 °C turns the hydrophobicity “off”. The theoretical calculations of optical properties demonstrate that the laser-induced oxide layer formed during the laser texturing significantly influences the surface optical behavior. Consequently, the interference of light reflected by the air–oxide and the oxide–metal interfaces should not be neglected and enables several advanced approaches to exploit such optical properties.

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Section: Influence Of the Low-temperature Annealing On The Wettabilitmentioning

confidence: 74%

Comment on “Bioinspired Reversible Switch between Underwater Superoleophobicity/Superaerophobicity and Oleophilicity/Aerophilicity and Improved Antireflective Property on the Nanosecond Laser-Ablated Superhydrophobic Titanium Surfaces”

Gregorčič

2020

ACS Appl. Mater. Interfaces

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“…These samples were textured by femtosecond [152,163], picosecond [112] and nanosecond [104,114,134,146] laser pulses. Moreover, similar transitions have also been observed on oxides that were not induced by laser radiation [159][160][161]. All of this indicates that the mechanism of wettability transition after laser texturing should be universal and should not characteristically depend on a specific metal or metal alloy as well as on specific (laser-)processing parameters [154].…”

Section: The (Super)hydrophilic-to-(super)hydrophobic Transitionmentioning

confidence: 60%

“…When surfaces are exposed to ionizing radiation, this also significantly influences surface wettability [161,171,172].…”

Section: Fabrication Of Multiscale -Cavities By Laser Texturingmentioning

confidence: 99%

Laser Surface Engineering for Boiling Heat Transfer Applications

Zupančič

Gregorčič

2021

Materials With Extreme Wetting Properties

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Nucleate boiling is inseparably connected with our everyday life. It is not only utilized in simple tasks like cooking, but it is also important for applications on various scales, ranging from enormous nuclear power plants to miniature microelectronics. This widespread integration is the result of its ability for effective heat transfer at low temperature differences between the heated surface and the surrounding fluid. The surface wettability undoubtedly influences the boiling heat transfer, but the observed behaviour cannot be explained without taking into account the surface topography and chemical modifications due to intense boiling processes. This chapter demonstrates how nucleate boiling enhancement can be achieved on surfaces with various wetting properties and specific micro/nano topographical features, fabricated using a straightforward, robust and scalable laser texturing approach. We discuss the basics of nucleate boiling and how it is affected by surface wettability; provide a fundamental background of laser surface engineering and its ability to achieve extreme wetting properties; and finally demonstrate the applicability of the laser-textured surfaces in enhancing and controlling nucleate pool boiling of different fluids. We show how laser surface engineering decreases the wettability effects on the key boiling parameters andin this wayensures more stable heat transfer performance.

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“…It is likely that the smaller grain size in SiC was responsible for more uniform corrosion. The authors carried out further XPS survey scans on the samples before and after oxidation and an increased oxygen peak was clearly observed for all the samples, further confirming surface oxidation [8]. The authors also performed water absorption (capillary wicking) measurements and all the irradiation samples were found to act as wicking surfaces after irradiation as result of the morphological changes due to localized corrosion [8].…”

Section: Surface Morphology and Chemistry Studiesmentioning

confidence: 77%

“…Surface energy measurement was also carried out at GIF, with SNL using a four-liquid approach through the determination of the polar (Lewis acid-base) and Lifshitz-van der Waals (includes Debye, Keesom, and London dispersion interaction) components of the surface energy. (Readers are requested to refer [8] for further details on surface energy measurement). Specifically, the four fluids used were deionized water, ethylene glycol, glycerol, and diiodomethane.…”

Section: Methodsmentioning

confidence: 99%