title: Wettability of nanoengineered dual-roughness surfaces fabricated by UV-assisted capillary force lithography.
abstract: Micro- and nanoscale combined hierarchical polymer structures were fabricated by UV-assisted capillary force lithography. The method is based on the sequential application of engraved polymer molds with a UV-curable resin of polyurethane acrylate (PUA) followed by surface treatment with a trichloro(1H,1H,2H,2H-perfluorooctyl) silane in vapor phase. Two distinct wetting states were observed on these dual-roughness structures. One is "Cassie-Wenzel state" where a water droplet forms heterogeneous contact with microstructures and homogeneous contact with nanostructures. The other is "Cassie-Cassie state" where a droplet makes heterogeneous contact both with micro- and nanostructures. A simple thermodynamic model was developed to explain static contact angle, hysteresis, and wetting transition on dual-roughness structures.
authors: School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea.
authors: Hoon Eui
authors: HE
authors: Jeong
authors: Moon Kyu
authors: MK
authors: Kwak
authors: Chan Ick
authors: CI
authors: Park
authors: Kahp Yang
authors: KY
authors: Suh