Fluid drag reduction on superhydrophobic surfaces coated with carbon nanotube forests (CNTs)

The slippage effect at the interface between a confined fluid and the surface around it has a potential application in microfluidic and nanofluidic devices. To investigate the slippage effect of fluid on superhydrophobic surfaces, a series of rheological experiments are carried out for superhydrophobic surfaces coated with carbon nanotube forests (CNTs), which are prepared by the chemical vapor deposition method (CVD). The results show that such surfaces can create certain slippage effects for a fluid flowing over them and that the slip length is in accordance with the theoretical prediction as well as the value measured through other experimental methods. As the same trend is observed for both the theoretical and experimental slip lengths, the theoretical model can be used to optimize the superhydrophobic surfaces for the slippage effect or drag reduction. The superhydrophobic surfaces with considerable slippage effects have broad potential application in micro- and nanofluidic devices or biodevices to solve the fluid resistance problem.