Is it possible to find out what goes on at the molecular scale when oil paint dries, ages and degrades? Researchers of the NICAS partner project ‘Fundamental Molecular Understanding of Oil Painting Degradation‘ have published a new article where they use infrared spectroscopy to follow the fate of zinc ions in zinc white paint films. With the help of clever algorithms to analyse small changes in the infrared spectra, the researchers could track the exact molecular environment around zinc ions as they moved from pigment particles to the oil binding medium, and finally towards zinc soap degradation products. Importantly, these new results show that zinc carboxylates can be used as a marker for local chemical conditions, allowing researchers to gain information on molecular composition and the presence of water inside paint layers.

Overview of the different structures adopted by zinc carboxylates in the lifetime of a painting.

Marit Beerse, Katrien Keune, Piet Iedema, Sander Woutersen, Joen Hermans. Evolution of Zinc Carboxylate Species in Oil Paint Ionomers, ACS Applied Polymer Materials, 2020.

DOI: 10.1021/acsapm.0c00979