Desert Beetle-Like Superhydrophobic/Superhydrophilic TiO₂–Nanoparticle Patterned Fabric Surface for Fog Harvesting

Freshwater resources are essential for human survival, and fog harvesting has emerged as a sustainable solution to address water scarcity. Current research on fog harvesting has focused on developing surfaces with hybrid superhydrophobic–superhydrophilic properties by imitating beetles in the Namib Desert, which also face challenges in fog harvesting efficiency due to low precision, complex preparation, and high-cost issues. Further investigations are necessary to identify the optimal parameters and arrangements of superhydrophilic regions that can enhance water collection productivity. This study presents a simple approach by combining a spraying method with ultraviolet modification and masks to fabricate the superhydrophobic–superhydrophilic TiO2–nanoparticle patterned fabric. By optimizing the diameter, proportion, and distribution of superhydrophilic patterns on the fabric, the water collection rate has been improved to 609.10 mg·cm–2·h–1, which is 5.6 times that of a uniform superhydrophilic fabric. The action mechanism of pattern parameters on the water collection rate has been examined by designing the water droplet rolling-off test. Last but not least, this study also illustrates the potential of biomimetic superhydrophobic–superhydrophilic TiO2–nanoparticle patterned surfaces for enhancing fog harvesting, addressing both ecological and industrial water resource management needs.