Langmuir, 17 (14), 4251 -4255, 2001. 10.1021/la010269b S0743-7463(01)00269-4
Web Release Date: June 13, 2001

Copyright © 2001 American Chemical Society

Colloidal Particles of Ca(OH)2: Properties and Applications to Restoration of Frescoes

Moira Ambrosi, Luigi Dei,* Rodorico Giorgi, Chiara Neto, and Piero Baglioni*

Department of Chemistry and CSGI, University of Florence, via Gino Capponi, 9 I-50121 Florence, Italy

Received February 20, 2001

In Final Form: May 2, 2001

Abstract:

We studied the synthesis and characterization of Ca(OH)2 colloidal particles and their application to the restoration of wall paintings. Submicrometer Ca(OH)2 crystalline particles have been obtained by mixing equal volumes of NaOH and CaCl2 aqueous solutions with different degrees of supersaturation (from 2 to 10) and in the temperature range 60-90 C. The Ca(OH)2 particles are crystalline and have the appearance of hexagonal platelets with thicknesses of a few nanometers, as determined by scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, and atomic force microscopy techniques. The kinetic stability of dispersions of Ca(OH)2 particles in water and propan-1-ol has also been studied in view of their possible application in wall painting conservation. A successful example of this application to the restoration of Santi di Tito's wall paintings (16th century) in the Santa Maria del Fiore Cathedral in Florence is also reported.

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