Superhydrophobicity of 2D SiO2 hierarchical micro/nanorod structures fabricated using a two-step micro/nanosphere lithography

• Published in: Journal of materials chemistry 2012-01, Vol.22 (28), p.1435-1441
• Main Authors: Park, Hoo Keun, Yoon, Seong Woong, Do, Young Rag
• Format: Article
• Language: English
• ISSN: 0959-9428; 1364-5501
• DOI: 10.1039/c2jm31978k

In this study, dual-triangularly patterned micro/nanorod hierarchical structures were fabricated using a simple combination of the microsphere lithography-reactive ion etching (RIE) process and the nanosphere lithography-RIE process in order to fabricate superhydrophobic surfaces. For the comparison of the wetting properties of the various hierarchical structures, the micro/nanorod geometries were controlled by changing the diameter of the microrod and/or nanorod under equal lattice constant and height conditions. Through the fabrication of two dimensional (2D) triangular SiO 2 nanorod arrays (diameter: ∼150 nm, lattice constant: 420 nm, height: ∼250 nm) on 2D triangular SiO 2 microrod arrays (diameter: ∼842 nm, lattice constant: 2 μm, height: ∼1 μm), the maximum contact angle (160.4°) of the SiO 2 micro/nanorod hierarchical structures was obtained via the subsequent coating of fluoroalkylsilane, leading to a strong superhydrophobicity. The facile two-step sphere lithography for the fabrication of superhydrophobic hierarchical structures on large scale glass wafers (2 inch) demonstrated that there are potential applications in the fields of microfluidic devices, lab-on-a-chip devices, and biological sensors. A superhydrophobic surface with dual-triangularly patterned micro/nanorod hierarchical structures can be fabricated over a 2 inch glass wafer using a combination of the microsphere lithography-reactive ion etching (RIE) and nanosphere lithography-RIE processes.