Flame-retardant surface treatments

Flame retardants mitigate the threat of fire from inherently flammable materials responsible for sustaining a high standard of living. Although bulk flame retardants have proven effective for many years, there is now increased interest in the use of surface treatments to localize flame-retardant chemistry at the exterior of a material, where combustion occurs, in an effort to preserve desirable bulk properties and minimize the amount of additive needed. This Review provides a historical overview that leads to the most promising surface treatments that will help pave the way for developing more effective and non-intrusive flame retardants in the future. The way in which a fire transpires, and the various chemistries and mechanisms used to counteract fire propagation, are discussed. Challenges that remain to improve current flame-retardant surface treatments are also addressed, as the success of these treatments depends on the scalability, durability and ability to impart desired functionality without conferring environmental problems.