Integrated super-hydrophobic and antireflective PDMS bio-templated from nano-conical structures of cicada wings

Abstract

Inspired by cicada wings that can greatly minimize the reflectivity on their surfaces over broad angles or frequency ranges due to the presence of tapered pillar arrays, we fabricated a polydimethylsiloxane (PDMS) positive replica of cicada wings, which demonstrated antireflective and super-hydrophobic characters. Firstly, the cicada wings were selected as a template to duplicate a SiO₂ negative replica. Then, the SiO₂ negative replica was used as a secondary template to prepare a PDMS positive replica. The resultant PDMS replica inherited the nano-conical structures and thus exhibited outstanding antireflective effect. A suppression of reflectance to a minimum of 0.7% that benefits from nano-cones has been achieved, since the path length and quantity of the incident light irradiated onto PDMS could be increased by incorporating anti-reflective and light scattering patterns. In the meantime, the PDMS replica demonstrates super-hydrophobicity due to the presence of nano-cone structures. The PDMS replica of cicada wings that possesses both anti-reflective and superhydrophobic properties may hold great promise for applications in anti-reflection and self-cleaning windows, in photovoltaic cells, telescopes, camera lenses, glass windows and beyond.