3D Gold Nanowire Networks with Tailorable Surface Wetting State: From Rose-Petal Effect to Super-Hydrophilicity

This study demonstrates the different wetting states that can be achieved by varying the diameter and density of nanowires in free-standing 3D gold nanowire networks. This network structure consists of nanowires oriented at 45° to the horizontal plane and interconnected from four different directions. Sessile drop measurements on these tailored nanostructured films show a transition from hydrophilic to hydrophobic behavior as porosity increases from 20% to 98%. With tailored porosity from 60% to 80%, this nanostructure can exhibit super-hydrophilicity. In addition, the highly porous (>90%) hydrophobic structures exhibit the rose-petal effect, where water droplets remain pinned to the surface. These novel results demonstrate the capability to precisely control surface wetting behavior through intricate designs of nanostructures, which are crucial for a wide range of applications, including liquid transport, microfluidic devices, and sensors.