Έλεγχος χημικής συμβατότητας και βελτίωση στερεωτικών λίθου με νανοτεχνολογία ; Assessment of chemical compatibility and amelioration of stone consolidants with nanotechnology

The necessity of developing novel materials for protection, consolidation and self-cleaning of building materials originates from the ever increasing atmospheric pollution, which induces considerable corrosion. To this end, and aiming at preserving the sustainability of monuments, as well as traditional and modern constructions, the present doctoral thesis developed novel nanotechnology materials, which show advanced properties and can be further produced on an industrial scale.Into this context, three novel consolidant and protective nanomaterials (STP-1, STP-2 and STP-4) were developed, which simultaneously combine self-cleaning, waterproofing and restoring the cohesion of the structure of building materials. The nanomaterials STP-1, STP-2 and STP-4 are environmentally friendly, their synthesis exhibits a small energy fingerprint and they are effectively applied on stone substrates of both monuments and modern buildings. The experimental study of this thesis consists of the following parts: (a) synthesis of transparent, hydrophobic and photocatalytically active nanocomposite materials SiO2-TiO2-PDMS with low energetic demand, (b) thorough physicochemical characterization, (c) application on real substrates and (d) evaluation of their effectiveness as protective, consolidating and self-cleaning materials.The synthesis of these nanomaterials was based on the sol-gel process after mixing titanium alkoxide (titanium tetra-isopropoxide, TTIP), silica alkoxide (tetraethyl orthosilicate, TEOS) and an organosilane (hydroxyl-terminated polydimethylsiloxane, PDMS). The synthesis was conducted in room temperature in the presence of oxalic acid (Ox), the concentration of which increases gradually in the three compositions, STP-1, STP-2 and STP-4. The numbers accompanying the compositions 1, 2 and 4 represent the low, intermediate and high concentration of Ox, respectively. Following their synthesis, the nanomaterials were thoroughly studied with respect to their physicochemical characteristics in order to test and ...