Development of a multifunctional nanocomposite system for protection, consolidation and microbial growth prevention of porous stones: A case study for the conservation of tuff

In this work, innovative, sustainable, multifunctional surface treatments for tuff protection that combine water-repellency, consolidating function and long-lasting antimicrobial activity were developed and tested. In particular, different water-based formulations were prepared by adding to a commercial polysiloxane treatment a biocide against biodeterioration, or clay nanoparticles to strengthen the tuff or their combination where the biocide was partially loaded into the nanoclay to join protective, consolidant and long-lasting biocide activity. The last formulation showed the best overall performances, since the constituents synergically improve its water-repellency and aggregative effectiveness without changing the color. Moreover, all surface treatments showed promising antimicrobial activity.