Antireflective polymer composites with carbon nanomaterials modified by oxygen plasma

This study investigates the properties of epoxy resin reinforced with carbon nanomaterials (graphene and multi-walled carbon nanotubes “Taunit M” and “Taunit MD”), focusing on their structural and optical characteristics, as well as the effects of atomic oxygen (AO) exposure, which is crucial for the application of such composites in low Earth orbit (LEO) conditions. Exposure to AO in LEO, with an average energy of ~5 eV, leads to the surface erosion of composites, resulting in significant mass loss. Experimental results indicate that the average erosion yield (Rm) is 1.07·10–23 g/atom for the composite with “Taunit M” filler, 1.21·10–23 g/atom for “Taunit MD”, and 8.56·10–24 g/atom for the graphene-filled composite. This effect occurs because carbon fillers undergo the oxidation and chemical sputtering under AO exposure, a typical behavior for materials used in space environments. After irradiation with an AO fluence of (1.7–30.0)1020 atom/cm², a significant decrease in reflection coefficients (both specular and diffuse) is observed across a broad spectral range (0.2–25 µm). Specular reflection decreased by 1.4 times for pure epoxy resin, and by 9.9, 15.8, and 13.6 times for samples filled with graphene, “Taunit M”, and “Taunit MD”, respectively. Diffuse reflection from the pure epoxy decreased by 1.2 times, while for graphene-, “Taunit M”-, and “Taunit MD”-filled samples, it decreased by 5.3, 16.7, and 9.0 times, respectively. These findings indicate that modifying epoxy resin with carbon nanomaterials followed by AO irradiation leads to the formation of a surface layer with high anti-reflective properties. Such materials, treated with low-energy oxygen plasma, are highly effective for use in optical and optoelectronic systems of spacecraft, as well as in terrestrial applications requiring materials with high absorption and low reflection.