Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Durability assessment of nanostructured TiO2 coatings applied on limestones to enhance building surface with self-cleaning ability
Abstract Coating with nanostructured Titanium dioxide is able to enhance natural stone surface with self-cleaning and depolluting abilities; nonetheless, the durability of the coatings is a crucial issue to be assessed in relation to their potential for use in the context of the building heritage. In this paper, the resistance of coatings applied on a compact and a soft limestone, which differ in roughness, porosity and cohesion features, has been investigated. A peeling and a water impact test were performed and their effect on the coated surface was evaluated as film loss by qualitative/quantitative ESEM-EDS analyses. Self-cleaning effectiveness was assessed by performing a photodegradation test of Rhodamine B. Crack-free and conformable films showed a good anchorage to both limestones; after the durability tests the coated surfaces exhibited almost unchanged Ti/Ca ratios and self-cleaning efficiencies. Large adhesion failures and decreased Ti amounts were recorded where coatings were fissured; they especially occurred on the surface of the compact limestone, along with a reduced self-cleaning ability. High surface roughness accounted for a better adhesion of both crack-free and fissured films to the soft limestone, but some erosion of the coated surface, which affected this friable stone under the water impact, compromised their preservation. Nonetheless, good self-cleaning performances were still provided due to the retention of nanoparticles under the surface. The overall results support that preservation of nanostructured TiO2 coatings on the stone surface depends on the inherent characteristics of both films and supports; durability of the stone itself can play an important role.
Highlights Durability of nano-TiO2 coatings was investigated on a compact and a soft limestone. Ti loss and self-cleaning ability were checked after peeling and water impact tests. ESEM-EDS analyses and a photodegradation test of Rhodamine B were performed. Crack-free films well preserved Ti amounts and self-cleaning performances on stone surface. Low cohesion of the soft limestone compromised the durability of the coatings.
Durability assessment of nanostructured TiO2 coatings applied on limestones to enhance building surface with self-cleaning ability
Abstract Coating with nanostructured Titanium dioxide is able to enhance natural stone surface with self-cleaning and depolluting abilities; nonetheless, the durability of the coatings is a crucial issue to be assessed in relation to their potential for use in the context of the building heritage. In this paper, the resistance of coatings applied on a compact and a soft limestone, which differ in roughness, porosity and cohesion features, has been investigated. A peeling and a water impact test were performed and their effect on the coated surface was evaluated as film loss by qualitative/quantitative ESEM-EDS analyses. Self-cleaning effectiveness was assessed by performing a photodegradation test of Rhodamine B. Crack-free and conformable films showed a good anchorage to both limestones; after the durability tests the coated surfaces exhibited almost unchanged Ti/Ca ratios and self-cleaning efficiencies. Large adhesion failures and decreased Ti amounts were recorded where coatings were fissured; they especially occurred on the surface of the compact limestone, along with a reduced self-cleaning ability. High surface roughness accounted for a better adhesion of both crack-free and fissured films to the soft limestone, but some erosion of the coated surface, which affected this friable stone under the water impact, compromised their preservation. Nonetheless, good self-cleaning performances were still provided due to the retention of nanoparticles under the surface. The overall results support that preservation of nanostructured TiO2 coatings on the stone surface depends on the inherent characteristics of both films and supports; durability of the stone itself can play an important role.
Highlights Durability of nano-TiO2 coatings was investigated on a compact and a soft limestone. Ti loss and self-cleaning ability were checked after peeling and water impact tests. ESEM-EDS analyses and a photodegradation test of Rhodamine B were performed. Crack-free films well preserved Ti amounts and self-cleaning performances on stone surface. Low cohesion of the soft limestone compromised the durability of the coatings.
Durability assessment of nanostructured TiO2 coatings applied on limestones to enhance building surface with self-cleaning ability
Calia, Angela (Autor:in) / Lettieri, Mariateresa (Autor:in) / Masieri, Maurizio (Autor:in)
Building and Environment ; 110 ; 1-10
26.09.2016
10 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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