Trilayer Janus Membranes With Spatially Programmed Wettability for Postoperative Anti‐Adhesion

Postoperative tissue adhesion remains a significant clinical complication, creating a demand for biomaterial interfaces that prevent nonspecific biological attachment while maintaining tissue compatibility. Herein, we report a trilayer Janus membrane with spatially programmed wettability, fabricated via sequential electrospinning and electrospraying. The engineered architecture integrates a hydrophilic poly(lactic acid)/poly(ethylene glycol) (PLA/PEG) surface, a highly porous PLA intermediate layer, and a superhydrophobic PLA/wax composite coating. This design achieves pronounced wettability asymmetry, with a hydrophilic water contact angle of 44.7° and a superhydrophobic contact angle of 153.2°. Through systematic structural optimization, we achieved a hierarchical porous network (> 90% porosity) with robust mechanical strength (7.83 MPa) and stable interlayer integration. The superhydrophobic interface effectively repels liquid contaminants and exhibits excellent physical antifouling properties, while the hydrophilic layer promotes hydration and conformability. In vitro degradation studies demonstrate that the membrane maintains structural integrity during the critical postoperative healing window (7–14 days). This work establishes a scalable materials engineering strategy for constructing Janus membranes with tunable wettability for advanced anti‐adhesion applications.