Scratch-resistant sapphire nanostructures with anti-glare, anti-fogging, and anti-dust properties†

Although there has been significant interest in the novel material properties of bio-inspired nanostructures, engineering them to become mechanically durable remains a significant challenge. This work demonstrates the fabrication of sapphire nanostructures with anti-glare, anti-fogging, anti-dust and scratch-resistant properties. The fabricated nanostructures demonstrated a period of 330 nm and an aspect ratio of 2.1, the highest reported for sapphire thus far. The nanostructured sapphire sample exhibited broadband and omnidirectional antireflection properties, with an enhanced transmission of up to 95.8% at a wavelength of 1360 nm. The sapphire nanostructures also exhibited enhanced wetting performance and could mitigate fogging from water condensation or repel water droplets. Furthermore, owing to their sharp features, the fabricated structures could prevent particulate adhesion and maintain a 98.7% dust-free surface area solely using gravity. Furthermore, nanoindentation and scratch tests indicated that the sapphire nanostructures have an indentation modulus and hardness of 182 GPa and 3.7 GPa, respectively, which are similar to those of bulk glass and scratch-resistant metals such as tungsten. These sapphire nanostructures can be fabricated using high-throughput nanomanufacturing techniques and can find applications in scratch-resistant optics for photonics, electronic displays, and protective windows.