Double-structured zinc oxide nanowire architecture for robust superhydrophobicity and multifunctionality

• Robust ZnO films fabricated with nano/micro dual roughness via wet chemical methods. • Superhydrophobicity achieved with scalable and non-fluorinated surface modification. • Films show non-adhesive water behavior on flat surfaces. • Superhydrophobicity retained after 28 days in harsh conditions. Superhydrophobic surfaces have received tremendous interest for non-wetting applications such as self-cleaning, anti-icing, anti-bacterial, and anti-corrosion devices; however, the degradation of this superhydrophobicity, both over time and after exposure to various harsh environmental conditions, remains a major barrier to their widespread adoption. Here, we propose a scalable and low-cost method for developing robust superhydrophobic films with micro/nano open-porous structures. These films consist of double-structured zinc oxide nanowire vertical networks (DS ZnO NW) achieved through a wet chemical route and non-fluorinated grafting with hexadecyl trimethoxysilane. The surface exhibits remarkable superhydrophobicity, as evidenced by non-adhesive water droplets even on flat substrates. Additionally, the long-term stability of superhydrophobicity is proven as a water contact angle greater than 150° was retained even after a period of 28 days both at ambient conditions as well as after exposure to various harsh conditions including water immersion, high pressure, high humidity, strong base, and low temperature. The DS ZnO NWs developed here offer long-lasting superhydrophobicity without fluorination, positioning them as promising candidates for integration into a wide range of next-generation devices.