Superhydrophobic Polysilsesquioxane Nanospike/Glass Microfiber Composite for Separation of Oil–Water Mixtures

Superhydrophobic surfaces are renowned for their extreme hydrophobicity and versatility, showing great potential in numerous applications. Yet, the complexity of their production and susceptibility to mechanical and chemical degradation significantly limit their practical use. Herein, we introduce a straightforward one-step, solvent-free method for the in situ growth of polysilsesquioxane nanospikes (PNS) on glass microfibers, creating a hierarchical micronano composite material with excellent superhydrophobic properties, evidenced by a water contact angle of approximately 170° and a rolling angle below 3°. This composite exhibits exceptional stability against severe temperatures, humidity, and corrosive substances, including strong acids/bases and organic solvents, maintaining its superhydrophobicity even after repeated mechanical abrasion and oil contamination. Such resilience is attributed to the synergistic effect of its micronano hierarchical structure and the three-dimensional, covalently cross-linked structure of the PNS. Notably, it can easily and rapidly transform between superhydrophobic and superhydrophilic states via simple plasma treatment and surface re-engineering, facilitating its application in the highly efficient (>98%) separation of diverse and complex oil–water mixtures. This work opens promising avenues for applying superwettable surfaces in practical scenarios, especially those demanding durability and adaptability.