X-ray microscopic observations of Cassie-Baxter wetting behaviors

ORAL

Abstract

Cassie-Baxter wetting is prevailing in nature, for instance on lotus leaves and the body of the water strider, as well as on hydrophobic micropatterned surfaces, enabling to superhydrophobicity. Cassie-Baxter wetting is widely known to exhibit a flat bottom of a droplet on the top of the micropatterned surface. Occasionally a droplet has been found to be partially impaled into micropatterns and its bottom looks curved as observed with interference techniques, confocal microscopy, X-ray microscopy, and simulations. Here we clearly observe Cassie-Baxter wetting behaviors with high-resolution high-speed X-ray microscopy. We demonstrate that occurrence of flat or curved bottoms of a droplet is dependent on droplet volume, initial wetting, and micropattern geometry. Consequently, new interpretation for Cassie-Baxter wetting is suggested with respect to minimization of surface free energy.

*This research was supported by Global PH.D Fellowship Program(NRF-2015H1A2A1034133) and Basic Science Research Program through the National Research Foundation of Korea(NRF-2016R1D1A1B01007133).

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Presenters

  • Su Jin Lim

    • School of Advanced Materials Science and Engineering, Sungkyunkwan University
    • School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University

Authors

  • Su Jin Lim

    • School of Advanced Materials Science and Engineering, Sungkyunkwan University
    • School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University

  • Donggyu Kim

    • Department of Mechanical Engineering, KAIST
    • Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST)

  • Yeseul Kim

    • SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University
    • School of Advanced Materials Science and Engineering, Sungkyunkwan University
    • School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University

  • Hee Kyeong Park

    • School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University

  • Suyeon Jeong

    • School of Chemical Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University

  • Changhyun Pang

    • School of Chemical Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University

  • Seunghwa Ryu

    • Department of Mechanical Engineering, KAIST
    • Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST)

  • Byung Mook Weon

    • SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan Univ
    • SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University
    • School of Advanced Materials Science and Engineering, Sungkyunkwan University
    • School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University