Novel nanomaterials to stabilise the canvas support of paintings assessed from a conservator's point of view

During conservation treatment, consolidants and deacidifying agents can be added to the canvas of a painting to mechanically stabilise it and counteract the acidity that promotes degradation. In this study, new stabilising consolidants and deacidifying agents based on different nanoparticles (silica, calcium carbonate, magnesium oxide, cellulose nanofibrils and cellulose nanocrystals) were tested in comparison to traditionally used products. These products were applied onto different types of canvasses, and colour, gloss and pH changes were analysed. Conservators' subjective perceptions on the ease of application and the final visual results of the products were also assessed. Specifically, conservators were asked to examine the drying time and the ease of use of the products, as well as any changes in stiffness, darkening or whitening caused by the products on the canvasses. The best products were the ones based on calcium carbonate, magnesium oxide and cellulose nanocrystals. Cellulose nanofibrils are also promising consolidants because they are highly compatible with the chemical nature of painting canvasses.