Ethylene plasma polymerization on graphene nanoplatelets in a custom-built rotating cylindrical reactor

This study explores the surface modification of graphene nanoplatelets (GNPs) via ethylene plasma polymerization using a custom-built rotary cold plasma reactor. Pristine GNP powder was treated as micron-sized aggregates under low-pressure radiofrequency plasma. As no prior exfoliation step was employed, the resulting surface modification occurred primarily on the external surfaces of these aggregates, enabling homogeneous medium-scale deposition of polymeric material. FTIR confirmed the grafting of CH 2 and CH 3 groups. Raman spectroscopy showed increased defect density, with the I D /I G ratio increasing from 0.340 in pristine GNPs to 0.470 in plasma-treated samples (P-GNPs), and partial disruption of sp² domains. XRD revealed amorphous polymer formation, indicated by a broad band around 15°, which aligns with the amorphous halo typically associated with polymeric phases. TGA indicated a higher weight loss in plasma-treated samples (a 6 % mass loss in P-GNPs compared to 1.5 % in GNPs at 600°C) due to polymer decomposition. XPS confirmed the successful incorporation of saturated bonds (C-C/C-H). SEM showed semispherical polymer particles, with an average diameter of 261.2 ± 40.5 nm, on the GNP surface. This successful surface functionalization imparts the GNPs with chemical and morphological properties essential for improving their dispersion and interfacial adhesion within polymer matrices, thereby laying the groundwork for developing advanced nanocomposites.