Layer-by-layer deposition of a TiO2-filled intumescent coating and its effect on the flame retardancy of polyamide and polyester fabrics

New intumescent flame retardant coating made from poly(allylamine) (PAH), sodium polyphosphates (PSP) and TiO2 nanoparticles was designed using layer-by-layer assembly. The (PAH-PSP-PAH-TiO2)(n) (where "n" denotes the number of quadralayers) assembly has been deposited on silicon wafers in orderto evaluate its thickness as well as its topography by ellipsometry and by atomic force microscopy (AFM), respectively. According to AFM measurements, the coating appears smooth and continuous. The film exhibits a linear growth regime with a thickness of approximately 500 nm for 15 quadralayers (QL). However, when deposited on polyamide or polyester fabrics, this coating displays different morphologies as it was shown by scanning electron microscopy (SEM) analysis. The thermo- oxidative degradation and flammability properties of the coatings and their effect on polyamide and polyester fabrics have been evaluated by thermogravimetric analyses (TGA) and pyrolysis combustion flow calorimeter (PCFC) respectively. We have found that the coating acts efficiently in reducing the peak of the heat release rate (pHRR) value for polyamide fabric while very limited effect was observed on polyester fabric. (C) 2014 Elsevier B.V. All rights reserved.