title: Scalable fabrication of superhydrophobic hierarchical colloidal arrays.
abstract: Here we report a scalable bottom-up technology for assembling hierarchical colloidal arrays with superhydrophobic surface. Non-close-packed (NCP) colloidal multilayers, which facilitate the formation of more hydrophobic surface than close-packed arrays due to a higher fraction of entrapped air in between colloidal particles, are first fabricated by a simple spin-coating technology. Uniform silica nanoparticles are then assembled on the NCP microsphere arrays by a second spin-coating process. After surface functionalization of silica particles with fluorosilane, the resulting hierarchical colloidal arrays exhibit superhydrophobic surface with high apparent water contact angle (159°) and low contact angle hysteresis (4.7°). The experimental results on both the wettability and contact angle hysteresis can be qualitatively explained by adapting the Cassie's model. This spin-coating-based colloidal self-assembly technology is compatible with standard microfabrication and enables large-scale production of superhydrophobic coatings that could find important technological applications ranging from self-cleaning diffractive optics to microfluidic devices.
authors.affiliation: Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA.
authors.forename: Hongta
authors.initials: H
authors.lastname: Yang
authors.forename: Peng
authors.initials: P
authors.lastname: Jiang
mesh_terms: D003102:Colloids / Q000138:chemical synthesis / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D010316:Particle Size; D012822:Silicon Dioxide / Q000138:chemical synthesis / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D003102:Colloids; D012822:Silicon Dioxide