MRS Bulletin

Technical Feature

Technical Feature

Materials Science Research for the Conservation of Sculpture and Monuments

George W. Scherer, Robert Flatt and George Wheeler

Mountains give the illusion of durability because their grand scale hides the continual weathering of their surfaces. When the same stone is used to create a sculpture, the loss of a few millimeters suffices to spoil, or even eliminate, the features of a face; the rate of loss may be surprising, but it is not necessarily unnatural.

George W. Scherer is a professor in the Department of Civil & Environmental Engineering at Princeton University and a member of the Princeton Materials Institute. He primarily studies the mechanisms of deterioration of concrete and stone, particularly by crystallization of ice and salts in the pores.

Scherer received his BS and MS degrees in 1972 and his PhD degree in materials science in 1974, all from the Massachusetts Institute of Technology, where his thesis work was on crystal growth in glass. From 1974 to 1985, he was at Corning Glass Works, where his research included optical-fiber fabrication, viscous sintering, and viscoelastic stress analysis. The latter work was the subject of his first book, Relaxation in Glass and Composites (Wiley, 1986).

From 1985 through 1995, he was a member of the Central Research Department of the DuPont Company, where his work focused principally on sol-gel processing and especially drying. In collaboration with Jeff Brinker of Sandia National Laboratories, he wrote the book Sol-Gel Science (Academic Press, 1990). In addition, Scherer is the author of approximately 170 papers on glass and sol-gel science, and he holds nine U.S. patents. In 1997, he was elected to the National Academy of Engineering.

Scherer can be reached by e-mail at

Robert Flatt is a postdoctoral researcher at Princeton University. His past research involved the study of dispersion and rheology of hydraulic binders, the development of tailored mortars for the conservation of Roman mosaics, and the modeling of sulfur dioxide dry deposition on limestone and sandstone. His current work focuses on salt crystallization, conducting direct measurements of crystallization pressure in porous substrates, and integrating non-ideal thermodynamics into the calculation of these pressures. He is also involved in the development of particle-modified consolidants for the restoration of stone.

Flatt received his diploma (1994) in chemical engineering and his PhD degree (1999) in materials science, both from the Swiss Federal Institute of Technology in Lausanne (EPFL).

He can be reached by e-mail at

George Wheeler is Research Chemist in the Sherman Fairchild Center for Objects Conservation at the Metropolitan Museum of Art, where he has worked for over 20 years. His research focuses on the conservation of stone, and he has published widely in that area. Wheeler received a BA degree in art history from Muhlenberg College, an MA degree in art history from Hunter College, a graduate Certificate in Art Conservation, and MS and PhD degrees in chemistry from New York University. His book, Alkoxysilanes and Stone Consolidation, with co-author Elizabeth Stevenson Goins, will be published by the Getty Conservation Institute.

Wheeler can be reached at the Sherman Fairchild Center for Objects Conservation, Metropolitan Museum of Art, 1000 Fifth Ave., New York, NY 10028, USA.