Structures and gas-sorption properties of carbonaceous film prepared by radio-frequency sputtering of polysaccharides pectin

Carbonaceous films with microcolumnar layer have been prepared by radio-frequency sputtering of polysaccharides pectin. The repeated sputtering has developed the densely packed seamless microcolumns, which are separated by the narrow grooves. The residual film stress has formed the honeycomb-patterned ridges. X-ray photoelectron spectroscopy and energy dispersion spectroscopy revealed the inclusion of nitrogen in the film constituents. The film surface is hydrophilic mainly due to the polar functional groups, such as the carboxyl and amino groups. Nitrogen adsorption measurement revealed that the specific surface area of the film was no less than 109 m2/g. Impedance analysis of the film-coated quartz crystal resonator clarified that the film had the higher adsorption capacities to the polar and cohesive vapors, such as ethyl alcohol. The adsorption of organic vapors has not induced the viscoelastic changes in the film.