Art conservation gets a boost with nanotechnology
“A new European project, aimed at transforming the cleaning and conservation of art work, had its official opening meeting this week at the University of Florence, on 16 and 17 January 2011.
The 3 year NanoForArt project, involving nine European partners (universities, museums and companies) and the Museum of Anthropology, Mexico City, will be developing and testing new methods and materials for conserving and cleaning paintings, murals, frescos and other art works. These are intended to replace the use of synthetic polymers and pure solvents which, over time, can do more harm than good.
Since the 1930s, restorers and conservators have made use of newly available substances for cleaning and restoring works of art, often with excellent short-term effect. Synthetic polymers, for example, have been widely applied as varnishes to protect murals and frescoes, revealing once again their original bright colours.
“There are good results on a short timescale, but then the polymers start degrading and increase the degradation of the materials of the original works of art”, says Piero Baglioni, Professor of Chemistry and Director of the Centre for Colloids and Surfaces at the University of Florence, and coordinator of the NanoForArt project, speaking in advance of the meeting.
The degradation process is one that can often occur in the absence of any varnish, but can be made worse in the presence of varnish. Over time, chemical reactions take place between the plaster underlying a fresco, for example, and air pollutants, which turns a key substance in the plaster – calcium carbonate – into calcium sulphate in a process known as salt crystallisation. The accumulation of calcium sulphate creates mechanical stress which can cause lifting and detachment of the paint layer, and cracks in the plaster. The result is a visible flaking and powdering, and fading of colour. Where protective polymers have been applied, this salt crystallisation process occurs more deeply in the pores as they become blocked by the polymer, which intensifies the degradation process. The new NanoForArt project is addressing this by taking recent developments in the field of nanotechnology and applying them to art conservation and cleaning.
Baglioni and his colleagues have developed new types of materials called consolidants, for protecting frescos and other paintings. These are designed to be chemically more compatible with the substrates underlying the paint layer of frescoes and murals. These have been used successfully in case studies to prevent degradation, including for pre-Colombian wall paintings at the archaeological site of Mayapan, Yucatàn, Mexico.
“We apply a chemical to convert the sulphate back into carbonate, so that there is no change in the chemical composition of the original artefacts painted, for example, by Giotto or Michaelangelo,” he explains.
(For more details, see the full feature “Innovations in the Conservation of Works of Art” by Baglioni and his post-doctoral colleague David Chelazzi).
The project will also be tackling the problem of damage that can result from the use of solvents for removing dirt. The immediate results of using pure solvents for this purpose can be impressive. But solvent and its residues can accumulate inside the pores of the underlying substrate, which can lead to distortion and deterioration.
The NanoForArt approach is to adapt micro-emulsions, developed for the purpose of drug delivery, for use as new cleaning agents. The micro-emulsions contain tiny droplets of solvent. These droplets interact gently with dirt layers, enabling conservators to have more control in the cleaning of a surface. This also minimises the danger for the conservator of solvent exposure, by reducing the quantity of solvent needed to as little as ten per cent compared to the use of pure solvent, according to Baglioni.
NanoForArt partners will develop and tailor these systems more precisely for use on different types of paintings. Partners who are on stand-by to test the new technologies on sample materials include the National Museum of Denmark, the Museum of Anthropology in Mexico City. Companies in Germany and Italy are also involved to manufacture the resulting products so that they can be commercially available on a wide scale.
It’s his passion for art that has led Baglioni to increasingly apply his research in physics and chemistry to art.
“A few years ago it was just a hobby – because we like art. Now maybe 25 to 50 per cent of our science is devoted to conservation,” he told Heritage Portal.”
BRON: Julie Clayton, Heritage Portal
En zie www.nanoforart.eu/