Super-hydrophobic PDMS surface with ultra-low adhesive force

Abstract

Rough polydimethylsiloxane (PDMS) surface containing micro-, submicro- and nano-composite structures was fabricated using a facile one-step laser etching method. Such surface shows a super-hydrophobic character with contact angle higher than 160 degrees and sliding angle lower than 5 degrees, i.e. self-cleaning effect like lotus leaf. The wettabilities of the rough PDMS surfaces can be tunable by simply controlling the size of etched microstructures. The adhesive force between etched PDMS surface and water droplet is evaluated, and the structure effect is deduced by comparing it with those own a single nano- or micro-scale structures. This super-hydrophobic PDMS surface can be widely applied to many areas such as liquid transportation without loss, and micro-pump (creating pushing-force) needless micro-fluidic devices.