Affiliation:
1. Department of Mineralogy and Petrology Faculty of Sciences University of Granada Avenida Fuentenueva S/N Granada 18002 Spain
2. School of Chemical and Process Engineering University of Leeds Woodhouse Leeds LS2 9JT UK
3. Escuela de Estudios Árabes Spanish National Research Council (CSIC) Cuesta del Chapiz 22 Granada 18010 Spain
4. Conservation Department Council of the Alhambra and Generalife Calle Real de la Alhambra S/N Granada E‐18009 Spain
Abstract
AbstractIn this work, the potential of bio‐inspired strategies for the synthesis of calcium sulfate (CaSO4·nH2O) materials for heritage conservation is explored. For this, a nonclassical multi‐step crystallization mechanism to understand the effect of calcein– a fluorescent chelating agent with a high affinity for divalent cations— on the nucleation and growth of calcium sulfate phases is proposed. Moving from the nano‐ to the macro‐scale, this strategy sets the basis for the design and production of fluorescent nano‐bassanite (NB‐C; CaSO4·0.5H2O), with application as a fully compatible consolidant for the conservation of historic plasterwork. Once applied to gypsum (CaSO4·2H2O) plaster specimens, cementation upon hydration of nano‐bassanite results in a significant increase in mechanical strength, while intracrystalline occlusion of calcein in newly‐formed gypsum cement improves its weathering resistance. Furthermore, under UV irradiation, the luminescence produced by calcein molecules occluded in gypsum crystals formed upon nano‐bassanite hydration allows the easy identification of the newly deposited consolidant within the treated gypsum plaster without altering the substrate's appearance.
Funder
Vicerrectorado de Investigación y Transferencia, Universidad de Granada
Ministerio de Ciencia e Innovación