Evaluating the impact of atomic oxygen surface cleaning on oil paint

In the conservation of cultural heritage surface, cleaning constitutes one of the most critical and frequently performed procedures. Historical approaches include “dry” methods, involving mechanical removal of dirt, and “wet” methods, which use water and solvents to eliminate contaminants. However, solvents can be toxic, surfaces can be sensitive to mechanical action or water and process control can be challenging in certain cases. To address these challenges and promote green methodologies, the MOXY project was initiated. It aims to develop a non-contact cleaning technique for cultural heritage objects using atomic oxygen (AO) cold plasma, which allows for non-liquid, non-thermal treatment1. Atomic oxygen is highly reactive with a short lifetime of a few milliseconds, likely leading to the oxidation of organic contaminants and the production of volatile byproducts. However, before applying this method to historical artifacts, it is crucial to understand how AO affects the underlying substrate material and to compare its effectiveness with more established cleaning methods. In the frame of this work experiments were focused on oil paints. The oxidation of oil is a well-studied process involving radical chain reactions2. By comprehending the potential outcomes of such chemical interactions and employing analytical methodologies, we can qualitatively and quantitatively assess the effects of AO treatment on the substrate. To this end, experiment was carried out on a number of fresh and aged simplified mock-up models of handmade oil paint. Subsequently, treated and untreated areas were analyzed to detect changes in the chemical composition of the binder, using EGA-MS for characterization of the binder polymeric structure, SPME GC-MS for investigation of the volatile organic compounds evolved from samples, and DSC for evaluation of radical activity. Finally, ATR-FTIR was employed to study the surface of the samples. Results presented in this poster display the initial analytical data and form a foundation for further research into the applicability of this technology for actual art objects. References: [1] Markevičius, T., N. Olsson, A. Nikiforov, G. Pastorelli, A. Suliga, I. Bonaduce, N. Yang, G. Van der Snickt, S. Pizzimenti, C. Pires, and K.J. van den Berg. 2023. Nascent oxygen innovation in art conservation: Cold atmospheric pressure plasma-generated monoatomic oxygen for the non-contact cleaning of works of art. In Working Towards a Sustainable Past. ICOM-CC 20th Triennial Conference Preprints, Valencia, 18–22 September 2023, ed. J. Bridgland. Paris: International Council of Museums. [2] Schaich, K. M. (2013). Challenges in Elucidating Lipid Oxidation Mechanisms: When, Where, and How Do Products Arise? In A. Logan, U. Nienaber, & X. Pan (Eds.), Lipid Oxidation (pp. 1–52). AOCS Press.