Hierarchical polymer micropillar arrays decorated with ZnO nanowires.

We introduce a simple and robust method for fabricating hierarchical fibrillar arrays based on polymer micropillar (microPLR) arrays decorated with ZnO nanowires (NWs) on mechanically flexible substrates. The hierarchical fibrillar arrays are fabricated by replica molding of polymer microPLR arrays on microfabricated silicon templates and subsequent solution-based growth of ZnO NWs. Fine control over the dimensions and aspect ratios of both the microelements and the nanoelements is demonstrated. The hierarchical microPLR/NW arrays show superhydrophobic surface properties, with the contact angle higher than that of planar surfaces and microPLR arrays without nanostructures. The fabrication strategy suggested here may be potentially extended to fabricate other organic/inorganic hierarchical systems for different applications.