Cold High-Frequency Plasma Versus Afterglow Plasma in the Preservation of Mobile Cultural Heritage on Paper Substrate

This article presents a comparison between the results obtained at the application of a conservation treatment in cold high-frequency (HF) and afterglow plasma on historical papers dating in the 19th century. This article is focused on plasma biocide effects and on the impact of active species from the two types of plasma on the surface, highlighted by mechanical and physical-chemical analyses. The working gas was nitrogen and the treatment time was varied from 5 to 10 and 15 min. The result of physical-chemical analyses as SEM, pH determination, color, and tensile strength analyses, as well as microbiological investigations, converges to the conclusion that a treatment of 10 min achieves a complete decontamination, and the impact of active species is less intense in the afterglow plasma as compared to the direct discharge in cold HF plasma.