Bioinspired Hairy Crab Claw Polymer Surface with Excellent Self-Cleaning Wettability in Muddy or Oil-Contaminated Water.

The hairy crab Eriocheir sinensis lives in muddy freshwaters such as ponds and paddy fields. The crab's claw features dense patches of setae and exhibits an excellent self-cleaning surface in muddy waters. This study examined the micronano structure and wettability properties of the crab claw. The results showed that the claw consists of 3D cross-linked fibers with a hierarchical micronano structure, and the main chemical composition of these fibers was determined chitosan molecules. The claw also has special superoleophobic and self-cleaning properties in muddy water. Inspired by the structure of the crab claw, 3D-layered micro/nanostructures with poly(vinyl alcohol)/chitosan/poly( N -isopropylacrylamide) were prepared by electrospinning and in situ polymerization. This novel bioinspired polymer surface exhibits superhydrophilicity in the air, superoleophobicity underwater (with an oil contact angle of 163°), and excellent self-cleaning potential in muddy water.