Pool boiling enhancement via biphilic surface comprising superhydrophilic TiO2 and superhydrophobic Teflon arrays

Chanwoo Park, Seongpil An, Taegun Kim, Yong Il Kim, Ali Aldalbahi, Mohamed El-Newehy, Sam S. Yoon

Research output: Contribution to journalArticlepeer-review


The ever-increasing power density overloads the heat removal capability of miniaturized power electronic devices and thus an efficient liquid cooling method needs to be strategized. Herein, we introduce a biphilic surface consisting of both superhydrophilic TiO2 and superhydrophobic Teflon. The purpose of this unique combination is to decrease the superheat (Tsat) by efficiently releasing vapor bubbles via the superhydrophobic surface and to increase the critical heat flux (CHF) using efficient wetting supplied by the superhydrophilic surface. The superhydrophilic TiO2 layer was deposited by the room temperature aerosol deposition method, whereas the superhydrophobic Teflon dots were deposited by the atmospheric supersonic cold spraying method. Each Teflon dot was 1 mm in diameter and the dots were patterned in the form of n×n arrays, where n varied from 1 to 5. The optimal CHF (187 kW·m−2), superheat, and effective heat transfer coefficient (4.6 kW·m−2·k−1) were observed for the 4 × 4 sample, beyond which the cooling effect deteriorated because of the excessive area covered by the Teflon dots. While the Teflon dots facilitated efficient bubble release, securing sufficient flow passage with the aid of a hydrophilic wetting area was also critical; thus the combination of the superhydrophobic and superhydrophilic surfaces was optimally balanced.

Original languageEnglish
Article number123675
JournalInternational Journal of Heat and Mass Transfer
Publication statusPublished - 2023 Mar

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2020R1A5A1018153) , NRF-2021R1A2C2010530 , and 2022M3J1A106422611. This research was supported by Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number : HI21C0049010021).The authors acknowledge King Saud University, Riyadh, Saudi Arabia, for funding this work through Researchers Supporting Project number (RSP-2021/30).

Publisher Copyright:
© 2022 Elsevier Ltd


  • Aerosol deposition
  • Pool boiling
  • Supersonic cold spraying
  • Teflon
  • TiO
  • Wettability

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


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