Stainless-steel-net-supported superhydrophobic COF coating for oil/water separation

This work reports the preparation and post-synthetic modification of COF named BTADHBD with perfluorooctyltriethoxysilane (POTS) to obtain a superhydrophobic COF coating. Through post-synthetic modification, the water contact angle (CA) of BTADHBD is increased from 83.7° to 153.2° without change of crystals morphology and structure. BTADHBD COF coating was prepared on the stainless steel net (SSN) through repeated growth, followed by post-synthetic modification using (±)-glycidol (Glc) and POTS to obtain the SSN-supported superhydrophobic BTADHBD@Glc@POTS coating with a water CA of 152.1°. The superhydrophobic BTADHBD@Glc@POTS coating showed high water-resistance, self-cleaning property and oil/water separation performance using simply gravity as driving force. For various oil/water mixtures, the oil/water separation efficiency was always up to 99.5% with oil flux above 70 L/(m 2 ·s). For 50 successive cycles of oil/water separation, the high oil/water separation efficiency (above 99.5%) remained unchanged, which is very promising for oil/water separation.