A robust superhydrophobic and superoleophobic surface with inverse-trapezoidal microstructures on a large transparent flexible substrate

A robust superhydrophobic and superoleophobic surface is demonstrated. On a large-size template of the transparent polydimethylsiloxane (PDMS) elastomer surface, perfectly ordered microstructures with an inverse-trapezoidal cross section are fabricated with two consecutive PDMS replication processes and a three-dimensional diffuser lithography technique. The hydrophobicity and transparency were improved by additional coating of a fluoropolymer layer. The robustness of superhydrophobicity was confirmed by the water droplet impinging test. This transparent, flexible, and superhydrophobic surface provides a new approach for self-cleaning surfaces.