Wettability Enhancement of Bio-Inspired Micro-Textured Polymeric and Carbon Surfaces

Polymeric surfaces with enhanced wettability have been a subject of growing interest and research because of a wide variety of applications in fabricating anti reflective, low friction, water repellent and anti-biofoulant surfaces. Further, carbon surfaces with ultra hydrophobic response add some more applications in the list such as in Bio-MEMS, and microfluidics because of some intrinsic properties associated with carbon as a material itself. We present a simple and robust method to enhance the wettability of polymer surfaces by micro-patterning. The patterns found on two different leaves, Elephant creeper (Argyreia Nervosa) and Nasturtium (Tropaeolum Majus) which show superhydrophobic behaviour because of hairy and micro textured surfaces respectively were bio-mimicked by micro-molding technique in different polymers, polydimethylsiloxane, polystyrene, and resorcinol-formaldehyde (RF) gel. Bio-mimicked polymer surfaces because of roughness induced my micro-texturing shows significant the enhancement in the wettability characteristics. Moreover, since RF gel is a polymer precursor to carbon, micro-patterned RF gel surfaces yielded ultra-hydrophobic carbon surfaces upon pyrolysis.  The methodology presented here in this work can be easily applied for fabricating large area stable ultra-hydrophobic polymeric as well as carbon surfaces directly by biomimicking the patterns found on natural plant leaves. Furthermore, the nano-imprint lithography was also used to diversify this novel approach of fabricating the ultra-hydrophobic surfaces by transferring the leaf patterns on various other polymers like poly ethylene terephthalate and poly methyl methacrylate surfaces.