Conservation of monuments by a three-layered compatible treatment of TEOS-Nano-Calcium Oxalate consolidant and TEOS-PDMS-TiO 2 hydrophobic/photoactive hybrid nanomaterialsConservation of monuments by a three-layered compatible treatment of TEOS-Nano-Calcium Oxalate consolidant and TEOS-PDMS-TiO 2 hydrophobic/photoactive hybrid nanomaterials Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2019-09-172018enIn the conservation of monuments, research on innovative nanocomposites with strengthening, hydrophobic and self-cleaning properties have attracted the interest of the scientific community and promising results have been obtained as a result. In this study, stemming from the need for the compatibility of treatments in terms of nanocomposite/substrate, a three-layered compatible treatment providing strengthening, hydrophobic, and self-cleaning properties is proposed. This conservation approach was implemented treating lithotypes and mortars of different porosity and petrographic characteristics with a three-layered treatment comprising: (a) a consolidant, tetraethoxysilane (TEOS)-nano-Calcium Oxalate; (b) a hydrophobic layer of TEOS-polydimethylsiloxane (PDMS); and (c) a self-cleaning layer of TiO 2 nanoparticles from titanium tetra-isopropoxide with oxalic acid as hole-scavenger. After the three-layered treatment, the surface hydrophobicity was improved due to PDMS and nano-TiO 2 in the interface substrate/atmosphere, as proven by the homogeneity and the Si-O-Ti hetero-linkages of the blend protective/self-cleaning layers observed by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and Fourier-Transform Infrared Spectroscopy (FTIR). The aesthetic, microstructural, mechanical and permeabile compatibility of the majority of treated substrates ranged within acceptability limits. The improved photocatalytic activity, as proven by the total discoloration of methylene blue in the majority of cases, was attributed to the anchorage of TiO 2 , through the Si-O-Ti bonds to SiO 2 , in the interface with the atmosphere, thus enhancing photoactivation.http://creativecommons.org/licenses/by/4.0/Materials115Kapridaki_et_al_Materials_11(5)_2018.pdfChania [Greece]Library of TUC2019-09-16application/pdf25.4 MBfree Kapridaki Chrysi Καπριδακη Χρυση Verganelaki Anastasia Βεργανελακη Αναστασια Dimitriadou Pipina Δημητριαδου Πιπινα Maravelaki Pagona Μαραβελακη Παγωνα MDPI Cement mortars Compatible Conservation Hydrophobic Limestone Monuments Nanostructured PDMS-SiO 2 -TiO 2 nanocomposite Self-cleaning TEOS-nano-Calcium Oxalate