Dziadkowiec, J., Cheng, H.-W., Ludwig, M., Ban, M., Tausendpfund, T. P., von Klitzing, R., Mezger, M., & Valtiner, M. (2022). Cohesion Gain Induced by Nanosilica Consolidants for Monumental Stone Restoration. Langmuir, 38(22), 6949–6958. https://doi.org/10.1021/acs.langmuir.2c00486
Mineral nanoparticle suspensions with consolidating properties have been successfully applied in the restoration of weathered architectural surfaces. However, the design of these consolidants is usually stone-specific and based on trial and error, which prevents their robust operation for a wide range of highly heterogeneous monumental stone materials. In this work, we develop a facile and versatile method to systematically study the consolidating mechanisms in action using a surface forces apparatus (SFA) with real-time force sensing and an X-ray surface forces apparatus (X-SFA). We directly assess the mechanical tensile strength of nanosilica-treated single mineral contacts and show a sharp increase in their cohesion. The smallest used nanoparticles provide an order of magnitude stronger contacts. We further resolve the microstructures and forces acting during evaporation-driven, capillary-force-induced nanoparticle aggregation processes, highlighting the importance of the interactions between the nanoparticles and the confining mineral walls. Our novel SFA-based approach offers insight into nano- and microscale mechanisms of consolidating silica treatments, and it can aid the design of nanomaterials used in stone consolidation.
Materials Characterization: 30% Biological and Bioactive Materials: 70%