Sandgrouse Feather-Inspired Multiscale Hierarchical Microstructured Surfaces via IICSA for Controlled Liquid...

Bioinspired surfaces show great potential for liquid behavior regulation, but their fabrication is constrained by limited area, poor replication of biological hierarchical structures, and inadequate morphological controllability. Herein, we report a design strategy inspired by both the multiscale hierarchical morphology and unique liquid-handling properties of sandgrouse belly feathers. Via "instability-induced crystallization self-assembly (IICSA)," we precisely replicate the feathers' "rachis-barb-barbule-chirality" multiscale hierarchical microstructured surface (>200 cm²) and core liquid "adhesion-capture" function. Specifically, the microstructured surface exhibits excellent droplet adhesion, capable of stably suspending 32 µL droplets vertically and 80 µL droplets horizontally against gravity, and achieves high-speed impact capture-suppressing rebound, jetting, and splashing at 2.62 m s^-1. Furthermore, the microstructured surface demonstrates exceptional oil-water separation performance, achieving oil removal efficiency below the detection limit of Fourier transform infrared spectroscopy (FTIR), which outperforms the 95%-99% efficiency of conventional gravimetric methods. Mechanistically, we reveal that the liquid regulation is synergistically governed by multi-level capillary action and contact line pinning. This study provides a simple, scalable, and controllable approach to construct bioinspired functional structures, enabling new multiscale hierarchical surface designs for high-purity separation and precise liquid manipulation.