DRAFT 12th International Congress on the Deterioration and Conservation of Stone Columbia University, New York, 2012 1 NANOMATERIALS FOR CONSOLIDATION OF MARBLE AND WALL PAINTINGS Stéphanie Duchêne, *1 Vincent Detalle, 1 Monica Favaro, 2 Franco Ossola, 2 Patrizia Tomasin, 2 Chiara De Zorzi 2 and Naida El Habra 2 1 Laboratoire de recherche des monuments historiques, USR 3224 (CNRS-MCC-MNHN), 29 rue de Paris, 77420 Champs sur Marne FRANCE 2 CNR-ICIS, corso degli Stati Uniti 4, 35127 Padova ITALY Abstract This paper presents the study of calcium alkoxides from their synthesis to the final application as CaCO 3 precursors for calcareous materials consolidation. These innovative nano-structured molecules have been specifically designed to reach the requirements of compatibility and effectiveness when consolidating cultural heritage carbonaceous substrates such as marble and wall paintings. The first step was the selection of solvents used to solubilize the alkoxide. Then we selected two types of substrates in order to test its performances: samples of weathered Carrara marble (5x5x1 cm) and wall paintings specimens of frescoes and a secco techniques of green earth, yellow ochre, azurite, lead-tin yellow and cinnabar-white lead mix. Variations of ultrasonic velocity, observations of the coatings by FEG-ESEM and spectrophotocolorimetric measurements were done to evaluate the consolidation effects of the alkoxides and the absence of side-effects such as whitening. The calcium triethylen glycol monoethyl ether (Ca(TEGmEE) 2 ) gave the best results in butanol for wall paintings and it gave good results for consolidation specifications in isopropanol for marble specimens. This work has been supported by a bilateral project in 2010 by both French and Italian Foreign Affairs Ministries. Further studies will be done on this class of materials within the NANOMATCH project (Nano-systems for the conservation of immoveable and moveable polymaterial Cultural Heritage in a changing environment FTP-ENV- NMP-2011-2183182). Keywords: wall paintings, marble, consolidation, nanoparticles, ultrasonic velocity, colorimetry, ESEM 1. Introduction The extensive use of commercial organic polymers over the last 50 years for historical conservation treatments of stone and wall paintings has shown its limits in terms of durability and retreatability. Tailor-made inorganic nano-sized molecules based on calcium alkoxides have been investigated as they are thought to be most likely the most compatible materials with these substrates, as calcite precursors, when facing up to sugaring or powdering issues. A preliminary study was done on calcium alkoxides synthesis (Favaro, Ossola et al. 2008)and on the selection of molecules by the evaluation of their solubility and stability in methanol, ethanol, isopropanol and butanol. Characterization of the compounds was carried out by NMR and FT-IR, their decomposition process by FT-IR and the final crystalline phases (portlandite, vaterite,