Laser-engineered microcavity surfaces with a nanoscale superhydrophobic coating for extreme boiling performance

Može, Matic (author), Senegačnik, Matej (author), Gregorčič, Peter (author), Hočevar, Matej (author), Zupančič, Matevž (author), Golobič, Iztok (author)

Functionalized interfaces enhancing phase-change processes have immense applicability in thermal management. Here, a methodology for fabrication of surfaces enabling extreme boiling heat transfer performance is demonstrated combining direct nanosecond laser texturing and chemical vapor deposition of a hydrophobic fluorinated silane. Multiple strategies of laser texturing are explored on aluminum with subsequent nanoscale hydrophobization. Both superhydrophilic and superhydrophobic surfaces with laser-engineered microcavities exhibit significant enhancement of the pool boiling heat transfer. Surfaces with superhydrophobic microcavities allow for enhancements of the heat transfer coefficient of over 500%. Larger microcavities with a mean diameter of 4.2 um, achieved using equidistant laser scanning separation, induce an early transition into the favorable nucleate boiling regime, while smaller microcavities with a mean diameter of 2.8 um, achieved using variable separation, provide superior performance at high heat fluxes. The enhanced boiling performance confirms that the Wenzel wetting regime is possible during boiling on apparently superhydrophobic surfaces. A notable critical heat flux enhancement is demonstrated on superhydrophobic surfaces with engineered microstructure showing definitively the importance and concomitant effect of both the surface wettability and topography for enhanced boiling. The fast, low-cost and repeatable fabrication process has great potential for advanced thermal management applications.

• Language: English
• Keywords: surface functionalization, laser surface engineering, hydrophobic surfaces, pool boiling, nucleate boiling, laser structuring
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Author Accepted Manuscript
• Year: 2020
• Number of pages: 24419-24431
• Numbering: Vol. 12, iss. 21
• PID: 20.500.12556/RUL-116531
• UDC: 536.24(045)
• ISSN on article: 1944-8244
• DOI: 10.1021/acsami.0c01594
• COBISS.SI-ID: 14158851
• Publication date in RUL: 27.05.2020

Record is a part of a journal

• Title: ACS applied materials & interfaces
• Shortened title: ACS appl. mater. interfaces
• Publisher: American Chemical Society
• ISSN: 1944-8244
• COBISS.SI-ID: 14731286

Secondary language

• Language: Slovenian
• Keywords: funkcionalizacija površin, laserski inženiring površin, hidrofobne površine, vrenje v bazenu, mehurčkasto vrenje, lasersko strukturiranje