Grafting of N-moieties onto octa-methyl polyhedral oligomeric silsesquioxane microstructures by sequential continuous wave and pulsed plasma

A functionalization of microstructures of polyhedral oligomeric silsesquioxane (POSS) to obtain substrates contain N-moieties, with a probable high selectivity of primary mines is demonstrated for the first time in a low pressure plasma process through a sequential continuous wave plus pulsed mode (CW + P). Selective grafting of N-moieties was performed across octa-methyl POSS micro-powder by substituting hydrogen atoms of the terminal methyl groups during nitrogen/hydrogen (N₂/H₂) gases plasma. As opposed to wet chemical functionalization approaches, the plasma method does not require reactive chemicals and is environmentally friendly. The results demonstrate the efficiency of the treatment (N/Si) reaches 7.1% with an indication of high NH₂ selectivity (NH₂/N). The amount of primary amines is determined from XPS data after 4-(trifluoromethyl) benzaldehyde (TFBA) chemical derivatization.