Colloids and Surfaces A: Physicochemical and Engineering Aspects 157 (1999) 333 – 340 Wettability of CaCO 3 surfaces Malvina G. Orkoula a,b , Petros G. Koutsoukos a,b, *, Michel Robin c , Olga Vizika c , Louis Cuiec c a Institute of Chemical Engineering and High Temperature Chemical Processes, PO Box 1414, GR-26500 Patras, Greece b Department of Chemical Engineering, Uniersity of Patras, Patras, Greece c IFP, Rueil Malmaison 92506, France Accepted 3 February 1999 Abstract The wettability of calcium carbonate, an important parameter in the evaluation of the interaction characteristics of materials used in conservation, was examined by measurements with the Wilhelmy plate technique. Heterogeneous surfaces consisting of glass and calcium carbonate were examined. Stable calcium carbonate layers were deposited on microscope glass slides using supersaturated solutions in which the equimolar concentrations of total calcium and total carbonate used ranged between 0.1 and 0.4 M, over a pH range between 9 and 12 and temperature between 25 and 80°C. In all cases amorphous calcium carbonate was deposited, the extent of surface coverage increasing with increasing supersaturation and temperature. Higher surface coverage of the glass slides with calcium carbonate yielded lower contact angles suggesting increased wettability of the heterogeneous surface. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Wettability; Calcium carbonate; Glass slides; Surface tension; Wilhelmy www.elsevier.nl/locate/colsurfa 1. Introduction The wetting of solid substrates by liquids is a significant parameter in a number of processes, such as spreading of liquid droplets on solids, with important application in the spraying of paints or agricultural chemicals, the penetration of ink in paper, the liquid absorbency or repel- lence of fabrics or the displacement of one liquid by another in oil recovery, etc [1,2]. The wettability of marble by various liquid chemical agents and/or rainwater is a very impor- tant factor both for understanding the erosion and weathering processes and also for the efficient application of chemical treatment methods used in conservation. The effective spreading of a protective film on marble’s surface or the penetration of a consoli- dant in the pores are greatly influenced by the wettability of marble by these substances. In cases where adsorption of ions or groups of ions from aqueous solutions on marble takes place, the wet- tability turns out to be a significant parameter * Corresponding author. Tel.: +30-61-997265; fax: +30- 61-993255 or +30-61-990987. E-mail address: pgk@iceht.forth.gr (P.G. Koutsoukos) 0927-7757/99/$ - see front matter © 1999 Elsevier Science B.V. All rights reserved. PII:S0927-7757(99)00047-3