Nature-inspired wettability-mixed titanium surface for efficient fog collection

• Multi-biomic pattern surpassing single-bionic limits. • Hexagonal-triangular units and spacing gradients resolve capture-desorption trade-offs. • Pattern I showed 221.24% higher WCR and 73.33% faster FDCT vs controls. • Multi-bioinspired design with honeycomb offers a scalable fog collection solution. Harvesting water from the air represents a sustainable solution to the water crisis faced by billions of people suffering water shortage. Given the immense demand for freshwater, improving efficiency remains an ongoing challenge. Inspired by desert beetles, cactus spines, honeycomb structures, and leaf veins, this paper presents an efficient fog collection Ti surface with superhydrophilic biomic pattern on hydrophobic surface. This multi-bioinspired approach synergises Laplace pressure and surface energy gradient, surpassing single-biomimetic designs regarding to fog collection efficiency. Specifically, the honeycomb structure addresses scalability issues, allowing for limitless expansion to a sufficiently large size, making it suitable for large-scale applications. The superhydrophobic Ti surface was fabricated using a combination of laser etching and fluorosilane modification. Secondary laser ablation was used to precisely etch a superhydrophilic pattern on the superhydrophobic surface. The pattern I promotes water adsorption, directional water transport and effective desorption under the help of surface energy gradient, Laplace pressure and desorption channel, significantly improving water collection efficiency. At 400 ml/h fog flow and 15 cm distance, the designed pattern I exhibits a water collection rate (WCR) of 6.2 kg·m -2 ·h -1 and collects the first droplet within 48 s. Compared to the reference, superhydrophilic, and superhydrophobic surfaces, WCR increased by 83.43%, 110.17%, and 221.24%, respectively. Meanwhile, the first drop collection time was reduced by 49.47%, 58.62%, and 73.33%. Additionally, this study explores the impact of surface inclination angle, laser etching speed, and number of etching cycles on fog water collection efficiency. The findings provide a new approach to fog water collection and demonstrate broad application prospects, such as droplet manipulation in microfluidic device and hiking water collection bottle. But the scalability remains a challenge for industrial applications. This paper leverages a multifunctional biomimetic structure to enhance efficiency while also addressing the scalable and templated adaptability for large-scale applications.