Self-assembled nanoparticles based fabrication of gecko foot-hair-inspired polymer nanofibers

Wafer-scale polymer nanofabrillar structures have been fabricated using the combination of colloidal nanolithography, deep-silicon etching, and nanomolding to mimic the nanostructure of gecko foot-hairs. The artificial surface features densely packed polymeric nanofibrils with super-hydrophobic, water-repellent, and "easy-to-clean" characteristics. The lateral dimension of the nanofibrils is as small as 250 nm and an aspect-ratio as high as 10:1 has been achieved without lateral collapse between neighboring fibrils. The method allows both fabrication of synthetic structures over a large area and direct integration of a flexible membrane to assist the array of nanofibrils in making intimate contact with uneven surfaces. A single nanofibril exhibits a mean adhesive force ranging from (0.91 +/- 0.34) nN to (1.35 +/- 0.37) nN. In the macroscopic scale, the nanostructured surface can adhere firmly to a smooth glass substrate and inherits the in-use, self-cleaning property of the setal nanostructures found in gecko lamellae.