Antimicrobial and self-cleaning coatings in building engineering: Materials, mechanisms and long-term performance for low-carbon environments

Surface engineering technologies, which can improve hygiene while lower the environmental impact associated with maintenance, have broader applicability and are being increasingly researched to meet the demand for low-carbon and net-zero buildings. Multifunctional solutions can be achieved with antimicrobial and self-cleaning coatings with applications to suppress microbial growth, restricting the spreading of surface or contact contamination and reducing water, energy and chemical-intensive cleaning processes. The goal of this review is to investigate recent advancements in these coatings, with a focus on their relevance for maintenance decarbonization from a building-engineering perspective. This Review discusses fundamental mechanisms such as antimicrobial activity and self-cleaning behavior along with emerging material systems and fabrication strategies that enable these developments for large-scale building applications. The key engineering performance characteristics, namely durability, weathering resistance, functional stability and compatibility with the substrate are examined thoroughly in realistic service conditions. The life-cycle carbon reduction attributable to these coatings is evaluated against two primary non-mutually exclusive approaches operational, through maintenance avoidance and embodied, through much greater service-life extension. Reviewing various field applications will focus on issues associated with scale, durability, environmental exposure. Ultimately, technical, economic and regulatory impediments are delineated, followed by frameworks directed towards implementation that can help facilitate the adoption of these coatings into sustainable building systems.