title: Tunable Surface Wettability of ZnO Nanoparticle Arrays for Controlling the Alignment of Liquid Crystals.
abstract: The control of the liquid crystal (LC) alignment is very important for both academic research and practical applications. LC molecules aligned on the ZnO nanoparticle arrays (ZnO NPAs) are demonstrated and the pretilt angles of LCs can be controlled by using ZnO NPAs with different surface wettability. The wettability of ZnO NPAs fabricated by the solution-based hydrothermal method can be controlled by changing the annealing temperature of the as-prepared ZnO NPAs. The measurements of the energy-dispersive spectra and photoluminescence have shown that the chemical properties of ZnO NPAs have been changed with the annealing temperature. Our results show that the pretilt angle of LCs can be tuned continuously from ∼0 to ∼90° as the contact angle of water on ZnO NPAs changes from 33 to 108°.
authors.affiliation: †Institute of Photonics System, ‡Institute of Lighting and Energy Photonics, and §Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan 711, Taiwan.
authors.forename: Yueh-Feng
authors.initials: YF
authors.lastname: Chung
authors.affiliation: †Institute of Photonics System, ‡Institute of Lighting and Energy Photonics, and §Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan 711, Taiwan.
authors.forename: Mu-Zhe
authors.initials: MZ
authors.lastname: Chen
authors.affiliation: †Institute of Photonics System, ‡Institute of Lighting and Energy Photonics, and §Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan 711, Taiwan.
authors.forename: Sheng-Hsiung
authors.initials: SH
authors.lastname: Yang
authors.affiliation: †Institute of Photonics System, ‡Institute of Lighting and Energy Photonics, and §Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan 711, Taiwan.
authors.forename: Shie-Chang
authors.initials: SC
authors.lastname: Jeng
keywords: ZnO nanoparticle arrays; liquid crystal alignment; pretilt angle; wettability