Critical length of nanowires for hydrophobic behavior

Abstract

This Letter investigates the wetting behavior on surface with well-controlled nanoscale structure. Water and water-alcohol droplets were brought to contact the surface electroplated by Ag nanowires. It is found that hydrophobic behavior becomes more pronounced as the length of the nanowires increases. A critical length of approximately 100 nm is observed, beyond which the contact angle approaches a steady value of 130degrees. In addition, the contact angle of water levels off around 160degrees when the length of the fluorine-coated Ag nanowires exceeds the critical value of 100 nm. The mechanism of the hydrophobic behavior on surface with nanoscale structure is proposed. (C) 2004 Elsevier B.V. All rights reserved.