Field Test of Self-Cleaning Zr-Modified-TiO2-SiO2 Films on Glass with a Demonstration of Their Anti-Fogging Effect.

Andraž Šuligoj,Roman Kunič,Aleš Ugovšek,Mohor Mihelčič,Olena Pliekhova,Jernej Starman,Urška Lavrenčič Štangar,Barbara Šubic,Nives Vodišek,Angelja Surca

doi:10.3390/ma12132196

Andraž Šuligoj, Roman Kunič + Show 8 more

Open Access

https://doi.org/10.3390/ma12132196

Copy DOI

Abstract

The number of commercial products claiming self-cleaning properties is rising and testing of long-term activity and durability of such coatings needs to be addressed more. The time-dependent changes of different characteristics like haze, transparency, and color are essential for transparent glazing materials. Herein, we aimed to examine whether the laboratory results obtained on the Zr-modified-titania-silica (TiZr) self-cleaning materials would translate to larger-scale outdoor-exposed testing. TiZr thin films were deposited via spraying onto float glass window surfaces and exposed into three different environments for 20 months. For comparison, a commercially available active SGG BIOCLEANTM glass and standard float glass were simultaneously exposed in the same conditions. It was shown that the self-cleaning property of either a commercial product or TiZr-coated float glass was not considerably effective in real field test conditions, although the previous laboratory tests showed pronounced photocatalytic activity of TiZr thin films. The inclination angle; however, was shown to have a considerable effect on the self-cleaning ability of samples, as did the rain patterns during the testing period. On the other hand, the anti-fogging effect of our TiZr material was very well expressed in controlled laboratory conditions (measuring droplet formation time) as well as in the real outdoor environment.

Highlights

Dust and pollution deposition on the operational surfaces of glass, concrete, metallic, textile, and plastic items is an actual problem, creating scientific and industrial interest in self-cleaning and self-sterilizing coatings [1,2]
The best compromise between photocatalytic activity and mechanical stability was achieved with coatings comprised of 10% Zr
Surface roughness and morphology of TiZr films were analyzed with Atomic force microscopy (AFM) and Scanning electron microscopy (SEM) microscopy (Figure 1) for dip-coated and for spray-coated samples—which were eventually used in the study

Summary

Introduction

Dust and pollution deposition on the operational surfaces of glass, concrete, metallic, textile, and plastic items is an actual problem, creating scientific and industrial interest in self-cleaning and self-sterilizing coatings [1,2]. The number of commercial products claiming self-cleaning, hydrophobic, or hydrophilic properties have currently reached a couple of dozens [3] and testing of long-term activity and durability of such coatings needs to be addressed more. Glass is an extremely important and useful material due to its transparency and is used for fenestration, automobile windshields, and display production and even as a construction material. Demand and number of transparent glazing coatings for solar photovoltaic (PV) panels have increased as well. The transparent coatings with different functionalities are in great demand for glass materials. The early publications claimed a self-cleaning effect of the coated glass even when it was not exposed to water [4]; another study [5] clearly showed, that additional service-like rinsing of self-cleaning glass would be necessary anyway

Objectives

Methods

Results

Conclusion