Room-Temperature Synthesis of Carbonaceous Films of Defined Thickness

Abstract

Thin carbonaceous films were prepared on top of a liquid amalgam of alkali metal (Li, Na, K) from gaseous perfluorocyclopentene, perfluorodecalin, perfluoronaphthalene, perfluorobenzene, perfluoro-2-butyne, perfluorohexane, perfluorobiphenyl, perfluorocyclobutane, perfluorocyclohexane, perfluoropyridine, perfluorobenzonitrile, and cyanuric fluoride. All the mentioned precursors are quantitatively dehalogenated by the alkali metal amalgam to give a composite film containing n-doped carbon with the interspersed alkali metal fluoride. The carbonaceous products from perfluoropyridine and cyanuric fluoride contain nitrogen, while the N/C proportion is close to that in the precursor. The kinetics of film growth was rationalized in terms of the electrochemical process in short-circuited corrosion cell. The presented mechanism of film growth at the gas/liquid interface upgrades the previously suggested model of carbonization of solid fluoropolymers by alkali metal amalgams. The method allows room-temperature growth of self-standing carbon thin films of precisely defined thickness.