Superhydrophobic and flame retardant polydimethylsiloxane coatings with layered double hydroxide and ammonium polyphosphate

The development of coatings with flame retardancy and superhydrophobicity is of great importance in practical application. Herein, a fluorine-free superhydrophobic and halogen-free flame retardant coating was constructed via simple dip-coating and efficient ultraviolet (UV) curing methods, using heavy cross-linking polydimethylsiloxane networks (HCPDMS) as low-surface-energy materials and hierarchical-structured layered double hydroxide-ammonium polyphosphate (LDH-APP) as organic-inorganic composite flame retardants. Owing to the such combination of hierarchical structure and low surface energy, these prepared coatings show striking repellency to various liquids, great self-cleaning and antifouling ability. Besides, they can resist the abrasion test by sandpaper for 30 cycles, the tape-peeling test for 200 cycles, and repeatedly kneading test. Meanwhile, these coatings offer good thermal stability and flame retardant, exhibiting an enhanced limiting oxygen index (LOI) from 18.0 % to 29.0 %. Moreover, a high oil/water separation efficiency of these coatings is over 95 % even after 16 separation cycles. Equipped with harmless to environment, facile preparation process, and excellent comprehensive performances, these coatings will have the potential for widespread application.