3D-printed bionic superhydrophobic surface with petal-like microstructures for droplet manipulation, oil-water separation, and drag reduction

Recently, bioinspired mushroom or reentrant mushroom microstructures have attracted intersts of researchers for their amazing water superrepellence property. However, basic principles of exquisite microstructures design for improving water repellence are still lacking. This paper reports a novel 3D-printed biomimetic superhydrophobic surface with petal-like microstructures inspired by the droplet pinning effect of nepenthes peristome. Then, parameters such as petal number, petal proportion and spacing distance are studied and optimized to improve water repellence, which is evaluated according to droplet bearing capacity. The results show that when the petal number is 4, the spacing distance is 100 μm, and the petal proportion is 50%, the petal-like structured surface achieves its maximum droplet bearing capacity. Comparing with the common mushroom microstructures, the maximum increase rate in bearing capacity is 58.3% for the optimized petal-like microstructures. Corresponding mechanism analysis attributes such superrepellence property to the sharp edge effect and the arch curve effect. Furthermore, the excellent water repellence enables the petal-like microstructured surface to be used for water droplets manipulation, oil-water separation, and captured-air drag reduction.