In an effort to develop highly functionalized flame retardant materials, hybrid nanocoatings are prepared by alternately depositing a positively charged polyaniline (PANi) and negatively charged montmorillonite (MMT) using the layer-by-layer (LbL) assembly technique. Carbon nanotubes (CNTs) are employed in polymer nanocomposites as effective reinforcement, where nanotubes are stabilized in MMT aqueous solution. The 3D structure and high density of CNTs deposited in the PANi/CNTs-MMT multilayers produce thicker and heavier coatings in comparison to the LbL assemblies without CNTs. Vertical and horizontal flame testing show that the incorporation of CNTs improves fire resistance. Additionally, cone calorimetry reveals that stacking two nanomaterials (MMT and CNTs) in a single coating shows a significant reduction in peak heat release rate (up to 51%), total smoke release (up to 47%), and total heat release (up to 37%) for the polyurethane foam. The enhancement of flame retardancy is attributed to a synergistic effect; MMT serves as a physical barrier that retards the diffusion of heat and gas. The addition of CNTs strengthens the thermal stability and high char yield. These results, coupled with the simplicity with which the LbL deposition is applied, present a viable alternative to halogen-free flame retardant nanocoatings to natural and synthetic fibers.

No abstract

Back Cover: In article number 2100233 by Chungyeon Cho and co‐workers, in an effort to develop highly functionalized flame retardant materials, polymer nanocomposites are assembled by alternately depositing polyaniline (PANi) and carbon nanotubes (CNTs), stabilized in montmorillonite (MMT) aqueous solution, via the layer‐by‐layer assembly technique. Incorporation of CNTs into a polymeric multilayer nanocoating of PANi and MMT exhibits a synergistic effect that improves thermal stability and fire resistance for the highly flammable polymeric materials such as cotton fabrics and polyurethane foams.