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.

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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