The Flexible Conical Lamella: A Bio-Inspired Open System for the Controllable Liquid Manipulation

Petals of the hydrophytic daisy, as a typical conical lamellar organ, enable the air trapping by forming a cavity-like structure during times of flooding for protecting their genetic materials, which serves as an essential strategy to resist the harsh environment. Inspired by the air capturing of hydrophobic petals, a series of hydrophilic flexible conical polyethylene lamellae (FCL-PE) with different apex angles are developed for controllable liquid manipulation: the smaller apex angle, the higher efficiency, and stability for liquid manipulation. Specifically, the FCL-PE system could manipulate over 19 times its own mass of liquid when the apex angle is approximate to 14 degrees, which remains rather stable even under external pressure. The highly efficient liquid manipulation of the FCL-PE is attributable to the synergistic effects of the Laplace pressure difference generated by the topological asymmetric conical structure and the capillary-induced liquid spreading by the precursor film on the planar lamella. In addition, the wrinkle-like nanostructures on the surface of FCL-PE are helpful for the pinning of three-phase contact line when interacting with liquid. Here, an alternative open system of FCL-PE is provided for the controllable liquid manipulation, which will shed new light on the designing of open systems for liquid transfer and collecting.