Reversible gel restores artwork.In an advance that could help conservationists restore paintings to their original glory, chemists have developed a cleaning product that switches from a free-flowing liquid to a viscous viscous /vis·cous/ (vis´kus) sticky or gummy; having a high degree of viscosity. vis·cous adj. 1. Having relatively high resistance to flow. 2. Viscid. gel. The researchers tested the material on a 14th-century painting from the National Gallery in Siena, Italy. Layers of resin applied after the painting's completion had, over the centuries, dulled the artwork's color. The gel brightened the test spot on the painting, and analyses of the gel after its use showed that none of the pigments had been removed from the original paint layer. The researchers describe their product in the Sept. 28 Langmuir. The so-called rheoreversible gel consists of a cleaning solvent mixed with a polymer called polyallylamine. Initially, the polymer was in a liquid form. However, when researchers bubbled carbon dioxide carbon dioxide, chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. through it, the polymer chains linked up. In this viscous state, the gel can be applied to a localized spot on a painting's surface where the cleaning solvent can do its work. Adding a bit of diluted di·lute tr.v. di·lut·ed, di·lut·ing, di·lutes 1. To make thinner or less concentrated by adding a liquid such as water. 2. To lessen the force, strength, purity, or brilliance of, especially by admixture. vinegar causes the gel to revert to a liquid that can be gently wiped away with a cotton swab "Q-Tip" redirects here. For the rapper, see Q-Tip (rapper). For the band, see Q-Tips (band). Cotton swabs (British English: cotton buds) are used in first aid, cosmetics application, and a variety of other uses. . Because other cleaning gels for artworks can't switch states like this, they are difficult to remove without disturbing the paint, particularly when they seep into the artwork's cracks and pores, says organic chemist Richard Weiss at Georgetown University Georgetown University, in the Georgetown section of Washington, D.C.; Jesuit; coeducational; founded 1789 by John Carroll, chartered 1815, inc. 1844. Its law and medical schools are noteworthy, and its archives are especially rich in letters and manuscripts by and in Washington, D.C. Weiss developed the gel with his colleagues at the University of Florence History The University of Florence evolved from the Studium Generale, which was established by the Florentine Republic in 1321. The Studium was recognized by Pope Clement VI in 1349, and authorised to grant regular degrees. in Italy. |
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