Nanoparticles in facade coatings: a survey of industrial experts on functional and environmental benefits and challenges

Integrating engineered nanoparticles (ENPs) into facade coatings is expected to offer considerable potential for improved or novel functionality, or even several functionalities at the same time (multifunctional materials). Little information is available about the tangible use of ENPs in facade coatings and the real improvements that their functionalities provide. In order to increase this information, we carried out a survey among selected coating manufacturers and ENP producers in Europe. We asked them about the improved functionalities enabled by ENPs, the quality of nano-enhanced facade coatings in comparison to conventional ones, and the handling of waste. The survey results indicated that the ENPs most frequently used in facade coatings in Europe were silver, titanium dioxide, and silicon dioxide. The most frequently mentioned potential benefits were ultraviolet-protection, water and dirt repellency (easy to clean), and antimicrobial properties. Improving environmental performance through the use of nano-enhanced facade coatings did not appear to be a focus for innovation. The survey also revealed mixed results in the comparison between nano-enhanced and conventional facade coatings: 36 % of respondents saw a notable improvement, 27 % noted a gradual improvement of functionalities, and 37 % detected no improvement over traditional materials. Some respondents mentioned a variety of tests that can be applied to investigate the quality of coating functionalities. These tests could be valuable in helping us to better understand the tangible improvements of nano-enhanced facade coating functionalities. Respondents were uncertain about how to properly handle the wastes resulting from nano-enhanced products