Authors: A. Jabbarzadeh
Affilation: The University of Sydney, Australia
Pages: 560 - 563
Keywords: wetting, surface nano-patterning, nano-droplet, nano- fluidics, slip-length, surface roughness, contact angle
Surface characteristic govern friction, flow, wettability and many other properties in solid-liquid interfaces. Wettability of surfaces is usually determined by measuring the contact angle of a single droplet put on the surface. Liquid repelling surfaces show larger contact angles. Surfaces can be made either liquid loving or liquid repelling (oleophobic, oleophilic in the case of liquid being oil). Wettability is believed to be affected by many properties, including temperature, surface-liquid interaction and physical topology of the surface, such as roughness. In this work the results of molecular dynamics simulations will be presented to show how nano-patterning of the surface affect the oleophobic properties of a surface. We have simulated nano-droplets of hexadecane coming into contact with model surfaces with various two dimensional features. The effects of the roughness and spread of this roughness patterns on the surface on the nano-droplet contact angle are studied. Our study shows one may control the oleophobic properties of the surface by adjusting these nano-patterns on the surface. Subsequently the same surfaces have been used to simulate and study flow of hexadecane in the nano-channels and correlations between the slip-length , droplet contact angle, and roughness are drawn.