Heat Shielding from Polyelectrolyte/Clay Coacervate Thin Film

The thermal protection of polymeric materials remains a significant concern across various engineering sectors due to the need to maintain their utility in high temperatures. Polymer–clay multilayer films have demonstrated excellent heat shielding performance, but the layer-by-layer deposition process involves numerous processing steps, which limits scalability. To address this challenge, a polymer–clay coacervate composed of poly(ethylenimine) (PEI), poly(acrylic acid) (PAA), and mica was deposited in a single step. To evaluate the thermal shielding, the PEI/PAA/mica coacervate coating was deposited onto poly(styrene) and exposed to the direct flame from a butane torch. The 17 μm thick polymer–clay film exhibited self-extinguishing behavior and provided substantial thermal insulation, significantly reducing the maximum temperature on the backside of the poly(styrene) plate. Thermal and chemical analyses revealed that, upon exposure to the flame, the polymer–clay coating generated an inorganic-rich barrier that effectively shielded the poly(styrene). This single-step deposition process offers a scalable approach for protecting polymeric materials at relatively high temperature.