Superhydrophobic porous silicon surfaces

In this paper, we present an inexpensive technique to produce superhydrophobic surfaces from porous silicon. Superhydrophobic surfaces are a key technology for their ability to reduce friction losses in microchannels and their self cleaning properties. The morphology of a p-type silicon wafer is modified by a electrochemical wet attack to produce pores with controlled size and distribution and coated with a n-alkysilane self assembled monolayer. Large contact angles are observed on such surfaces and the results are compared with classical wetting models (Cassie and Wenzel) suggesting a mixed Wenzel-Cassie behaviour. The presented technique represents a cost-effective means for friction reduction in microfluidic applications, such as lab-on-a-chip.