The pitcher plant has evolved its hierarchically grooved peristome to enhance a water-based slippery system for capturing insects with oil-covered footpads. Based on this, we proposed a hierarchically porous oil scoop (HPOS) with capillary-induced oil peel-off ability for repeatable spilled oil recovery. As HPOS scoops oil-water mixture, water passes through the hole while the oil is confined within a curved geometry. The filter in HPOS has three levels of porous structures; (1) 3D-printed mesh structure with sub-millimeter scale hole to filter out oil from an oil-water mixture, (2) internal micropore in fibers enhancing capillarity and water transport, (3) O₂ plasma-induced high-aspect-ratio nanopillar structures imposing anti-oil-fouling property with capillary-induced oil peeling. As the oil-contaminated HPOS contacts water, water meniscus rises and peels-off the oil immediately at the air-water interface. The oil-peel-off ability of HPOS would prevent pores from clogging by oils for reuse. The study demonstrated that the HPOS scoops highly viscous oil (up to 5,000 mm²·s⁻¹ of viscosity) with a high recovery rate (> 95%), leaving the filtered water with low oil content (< 10 ppm), which satisfies the discharge criterion of 15 ppm.

水罐厂已经改良了它的分层有沟纹的Peristome，以增强一种水基滑滑系统，该系统可以用油覆盖的脚垫捕获昆虫。基于此，我们提出了一种具有毛细孔引起的油剥落能力的分层多孔油勺（HPOS），以进行可重复的溢油回收。当HPOS收集油水混合物时，水会通过孔，而油则被限制在弯曲的几何形状内。HPOS中的过滤器具有三个级别的多孔结构。（1）3D打印的网状结构，具有亚毫米刻度孔，可从油水混合物中滤出油；（2）纤维中的内部微孔可增强毛细作用和水的输送；（3）O ₂等离子体诱导的高纵横比纳米柱结构，具有毛细管诱导的油剥落，具有抗油污特性。当受油污染的HPOS与水接触时，水弯液面上升并立即在空气-水界面处剥离油。HPOS的油剥落能力可防止油被毛孔阻塞而重新使用。研究表明，HPOS可以以高回收率（> 95％）收集高粘度油（粘度高达5,000mm²·s⁻1），而滤出的水却具有低油含量（<10 ppm），可以满足放电标准为15 ppm。