Biomimetic engineering for water harvesting: 3D printed solutions for arid regions.

Approximately one third of the Earth's surface has a climate that is currently considered arid, which in 2020 affected around 2.4 billion people. This extreme condition leads to challenges accessing water for agriculture, hygiene, and sanitation, amongst a myriad of others. Over millions of years, nature has evolved ingenious strategies for survival in such environments. One notable example is the Namib desert tenebrionid beetle, which collects water from fog using its elytra-a shell featuring a pattern of hydrophilic and hydrophobic surfaces. Inspired by this natural mechanism, we have studied 3D-printed green superhydrophilic/superhydrophobic hybrid surfaces and evaluated their water collection performance in a controlled climate chamber, which was designed to simulate arid conditions. The coated surfaces demonstrated a 4-5 fold improvement in water collection efficiency compared to uncoated samples. Both spiked and beetle-inspired designs were tested, revealing that larger spikes or bumps collected nearly twice as much water. Beetle-like channel structures also proved to be highly effective designs. Overall, it was observed that hybrid coatings outperformed fully hydrophilic or hydrophobic surfaces, suggesting that the increased complexity does indeed lead to greater water harvesting efficacy. These findings offer valuable insights into the design and engineering of efficient and sustainable water harvesting technologies for arid regions.