Pool Boiling Performance of Surfaces Produced by Femtosecond Laser Surface Processing and Copper Hydroxide Nanoneedle Growth

Justin Costa-Greger, George Damoulakis, Graham Kaufman, Suchit Sarin, Chase Pettit, Jeffrey Shield, Constantine Megaridis, Craig Zuhlke, George Gogos

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Copper hybrid functionalization that leads to copper hydroxide nanoneedles grown on top of femtosecond laser surface processed (FLSP) copper microstructures is experimentally studied in saturated pool boiling of distilled water at atmospheric pressure. FLSP was used to fabricate self-organized, hierarchical structures that lead to an inherently superhydrophilic surface. The hybrid scheme involved synthesizing copper hydroxide nanoneedles atop the FLSP microstructures using a dilute solution of sodium hydroxide and ammonium persulfate. The nanoneedles lead to increased surface area and altered cavity dimensions available for nucleation. In addition, a citric acid cleaning process was implemented to remove oxides from the FLSP surface before growing the nanoneedles. The FLSP surfaces with and without citric acid cleaning were tested up to critical heat flux to serve as baselines for comparisons with the hybrid functionalization scheme. Pool boiling results using the hybrid functionalization scheme revealed degraded performance for surfaces which incorporated copper hydroxide nanoneedles due to the increased volume of oxides present from the transition of copper hydroxide to copper oxide during heating. Scanning electron microscope images acquired after boiling tests revealed complete removal of the nanoneedles during testing, illustrating the nanoneedles' lack of durability under aggressive boiling conditions. The best performance was shown for a sample functionalized using FLSP only and without incorporating citric acid etching or nanoneedle growth. This surface achieved a 22% increase in the heat transfer coefficient compared to the polished surface at a heat flux of approximately 95 W/cm2, albeit at a reduced critical heat flux. Additionally, large degrees of pool boiling inversion were observed for surfaces which did not include the citric acid cleaning process. This observation points to a connection between the oxides produced from the FLSP process and boiling inversion for copper, suggesting that the presence of oxides and associated microstructures are responsible for boiling inversion on high thermal conductivity metals.

Original languageEnglish (US)
Title of host publicationProceedings of the 21st InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2022
PublisherIEEE Computer Society
ISBN (Electronic)9781665485036
DOIs
StatePublished - 2022
Event21st InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2022 - San Diego, United States
Duration: May 31 2022Jun 3 2022

Publication series

NameInterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM
Volume2022-May
ISSN (Print)1936-3958

Conference

Conference21st InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2022
Country/TerritoryUnited States
CitySan Diego
Period5/31/226/3/22

Keywords

  • copper hydroxide
  • femtosecond laser
  • hybrid functionalization
  • nanoneedles
  • pool boiling

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering

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