Paintings and gilt surfaces can be effectively and gently restored with water-based microemulsions
In the past, restoration of paintings and other old artwork often involved application of acrylic resins to consolidate and protect them. One of the most important tasks for modern restorers is thus to remove these layers, because it turns out that acrylic resins not only drastically change the optics of the treated artwork, but in many cases they accelerate their degradation. Italian researchers working with Piero Baglioni at the University of Florence have now developed a technique to effectively remove such old polymer layers from sensitive historic artworks. As the researchers report in the journal Angewandte Chemie, the new cleaning system involves only a tiny proportion of volatile organic compounds. "We have demonstrated the first successful application of a water-based system for the removal of an organic layer from artwork," says Baglioni. "In addition, our method is simpler and less invasive than traditional processes."
The scientists use an oil-in-water microemulsion with the organic solvent para-xylene as the oil component. An emulsion is a fine dispersion of droplets of one liquid in another liquid with which the first is not miscible. One example from our daily lives is milk. A microemulsion is an emulsion that forms spontaneously and is stable. It contains substances that act as emulsifiers. Because the individual drops are only nanometer-sized, the mircoemulsion is not milky and opaque, but clear and transparent.
The Italian researchers embedded their micoremulsion in a matrix of a modified type of cellulose—a material used as a thickener for emulsion paints. The matrix makes the cleaning agent viscous, so that it cannot enter very far into the pores of a painting. Its activity is limited to the outer layer, whilst deeper layers of paint do not come into contact with the xylene. The environment is protected as well, because of the very low concentration of volatile solvent, the evaporation of which is further limited by the matrix. The optical transparency of the system also allows the restorer to continuously monitor the cleaning process.
"We successfully cleaned a mural from the 15th century," reports Baglioni. This painting is located in the Santa Maria della Scala Sacristy in Siena. "It was covered with a 35 year old layer of acrylic from a previous restoration. Our new system allowed us to completely remove the undesirable shine. We were also able to clean another art work: a gilt frame from an 18th century painting."
Original publication:Piero Baglioni et al.; "Nanoscience for Art Conservation: Oil-in-Water Microemulsions Embedded in a Polymeric Network for the Cleaning of Works of Art"; Angewandte Chemie International Edition 2009
Smart skin that can respond to external stimuli could have important applications in medicine and robotics. Using only items found in a typical household, researchers have created multi-sensor artificial skin that's capable of sensing pressure, temperature, humidity, proximity, pH, and air ... more
Mercury contamination in water and on land is of worldwide concern due to its toxic effects on ecosystems and human health. Mercury toxicity is of particular concern to reptiles because they are currently experiencing population declines. Also, reptiles are ideal indicators of mercury conta ... more
A team of pioneering South Korean scientists have succeeded in producing the polymers used for everyday plastics through bioengineering, rather than through the use of fossil fuel based chemicals. This groundbreaking research, which may now allow for the production of environmentally consci ... more
Congenital myasthenic syndromes (CMS) are heterogeneous disorders in which the safety margin of neuromuscular transmission is impaired by one or more specific mechanisms. Since the advent of next‐generation sequencing methods, the discovery of novel CMS targets and phenotypes ha ... more
Myasthenia gravis (MG) with antibodies to muscle‐specific kinase (MuSK) is characterized by fluctuating fatigable weakness. In MuSK MG, involvement of bulbar muscles, neck, and shoulder and respiratory weakness are more prominent than in acetylcholine receptor (AChR) MG. MuSK au ... more
Because of the failure of many promising therapeutics identified in preclinical evaluation, funding sources have established guidelines for increased rigor in animal evaluations. The myasthenia gravis (MG) community of scientists has developed guidelines for preclinical assessme ... more
Development of organic single molecule magnets opens a great many of applications for magnetic materials and new memory technologies. Organic magnets are lighter, more flexible and less energy intensive in production than conventional magnets. Scientists from the laboratory of Dr. Benedetta ... more
The conservation of Mayan wall paintings at the archaeological site of Calakmul (Mexico) will be one on the subjects touched upon by Piero Baglioni (based at the University of Florence) in his invited lecture at the 3rd European Chemistry Congress in Nürnberg in September. In a special issu ... more