Contact angle measurements on superhydrophobic carbon nanotube forests: Effect of fluid pressure

In this paper the effect of pressure on the contact angle of a water drop on superhydrophobic carbon nanotube (CNT) forests is studied. Superhydrophobic CNT forests are obtained from a new and simple functionalization strategy, based on the gold-thiol affinity. Using a specifically devised experimental setup, we then show that these surfaces are able to withstand high excess pressures (larger than 10 kPa) without transiting toward a roughness-invaded state, therefore preserving their low adhesion properties. Together with the relatively low technical cost of the process, this robustness vs. pressure makes such surfaces very appealing for practical integration into microfluidic systems.