Polyimide-based nanocomposite coatings for quartz components in deployable space antenna structures

Large deployable reflector antennas require lightweight materials capable of withstanding ionizing radiation, repeated thermal cycling and mechanical loading without compromising radiofrequency performance. This work investigates commercial P84 polyimide supplied as a 25 wt% solution in N-methyl-2-pyrrolidone (NMP) and reinforced with few-layer graphene, few-layer hexagonal boron nitride and hybrid fillers up to 5 wt%. All formulations were deposited by spin coating on planar quartz substrates representative of antenna support-network components; selected films were subsequently detached to obtain freestanding specimens for tensile testing. The experimental study was contextualized using a previously developed SPENVIS/MULASSIS radiation-transport assessment for P84-based systems. Thermal, mechanical and surface characterization evaluated solvent removal, thermal stability, tensile behaviour, wettability, coating thickness and roughness. Filler incorporation generally increased stiffness while affecting surface morphology and strain at break. Pull-off tests before and after repeated thermal cycling assessed coating adhesion and interfacial stability on quartz substrates.