Robust superhydrophobic and flame-retardant coatings based on hierarchical epoxy textured with gas barrier structure; efficient oil-water separation devices under extreme conditions

Inspired by the biomaterial nacre, we report a versatile and facile strategy to rugged, flame retardant superhydrophobic materials by embedding a nacre-like montmorillonite (MMT) based gas barrier layer into hierarchical epoxy-resins. The well-aligned MMT layer imparted excellent oxygen and water barrier properties that rendered the coating surface water repellent yet protected the substrate materials from fire by suppressing heat and oxygen transfer. The hierarchical epoxy not only provided the robust superhydrophobic structure but offered strong adhesion to MMT layer. After application of this coating to a flammable sponge, it demonstrated superhydrophobicity with a contact angle of ∼153°. Furthermore, the material was rugged, resisting 1200 compression cycles and induced marked flame retardancy. The coated sponge delayed ignition (689% delay in ignition time) and promoted significant flame extinguishing property, compared with the uncoated material (demonstrated by LOI, CONE combustion, and fire scenario tests). Owing to its robustness and multifunctionality, the coated sponge was able to efficiently separate oil from multi-environments including strong corrosive, icy, boiling or vibrating mixtures. Additionally, the versatile application to wood, cotton, textile and other lignocellulosic substrates has been verified. This research opens up a new direction for durable waterproof and fireproof materials.