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Fabrication of a Superhydrophobic Surface from a Smectic Liquid‐Crystal Defect Array
Author(s) -
Kim Yun Ho,
Yoon Dong Ki,
Jeong Hyeon Su,
Kim Jung Hyun,
Yoon Eun Kyoung,
Jung HeeTae
Publication year - 2009
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200901135
Subject(s) - materials science , microscale chemistry , liquid crystal , fabrication , contact angle , conic section , nanoscopic scale , surface (topology) , substrate (aquarium) , nanotechnology , lamellar structure , surface finish , surface roughness , optics , composite material , optoelectronics , geometry , medicine , oceanography , alternative medicine , mathematics , mathematics education , pathology , physics , geology
A novel fabrication method is developed for the preparation of superhydrophobic surfaces. The procedure uses focal conic structures of semi‐fluorinated smectic liquid crystals (LCs) whose periodic toric focal conic domains (TFCDs) are prepared on a surface modified substrate. Reactive ion etching (RIE) on the periodic TFCD surface leads to a superhydrophobic surface with a water contact angle of ∼160° and a sliding angle of ∼2° for a 10 µL water droplet. The results show that this phenomenon is due to the development of a dual‐scale surface roughness arising from the nanoscale protuberance caused by applying the RIE process to the top of the microscale TFCD arrays. The unique surface behavior is further verified by demonstrating that RIE on a flat lamellar liquid crystal film, in which the director is aligned parallel with surface, results in a relatively low hydrophobicity as compared to when periodic TFCDs are subjected to REI. The observations made in this publication suggest that a new approach exists for selecting potential candidates of superhydrophic surface formation based on spontaneous self‐assembly in smectic liquid‐crystalline materials.