A Facile and Strategic Approach to Superhydrophobic Fibrous Structure with Biaxially Aligned Electrospun Porous Fibers

Electrospun fibrous structures can be developed superhydrophobic while remaining breathable. However, current electrospinning-based methods for developing superhydrophobicity require complex fabrication processes and multiple raw materials, lacking a facile approach to superhydrophobicity using electrospun fibers. Inspired by a cultural relic known as Plain Gauze Gown, a fibrous structure consisting two layers of porous fibers aligned in warp and weft directions by simple electrospinning is developed. Through investigation of wetting behavior, an unique Cassie-Baxter-"restoring" (CaRe) wetting contributing to a stable Cassie-Baxter state is unveiled in the developed structure. The CaRe wetting ensures that droplet stays on the upper-layer fibers even at a sparse inter-fiber distance, enabling strategically reaching superhydrophobicity by lowering structure solidity. Remarkably, the developed structure with water contact angle between 159 & DEG; and 162 & DEG; and roll-off angle from 10 & DEG; to 3 & DEG; has a water vapor transmission rate of 20.8 kg m-2 d-1, which is the highest value among all superhydrophobic electrospun structures reported, and it is also waterproof and semi-transparent. These features make the structure suitable for a wide range of applications, including developing waterproof, breathable, and superhydrophobic membrane with simple preparation and low cost, and as a surface layer for wearable electronics that facilitates sweat evaporation and prevents water intrusion. Inspired by a Chinese cultural relic known as Plain Gauze Gown, this work develops a fibrous structure consisting of two layers of porous fibers aligned in warp and weft directions by electrospinning. A unique Cassie-Baxter-"restoring" wetting contributing to a stable Cassie-Baxter state is unveiled. Remarkably, the developed structure is not only superhydrophobic, but also breathable, waterproof, and semi-transparent.image