Titanium dioxide and other nanomaterials based antimicrobial additives in functional paints and coatings: Review

Nanomaterials like titanium dioxide and zinc oxide are established photocatalysts that are well-known in a variety of functions. They can be applied in paint and coating as pigment while providing functionalities like antimicrobial. Antimicrobial property has been increasingly significant due to various diseases contributed by microorganisms that cause either long term or short-term effects to humans. However, the problem with the photodegradation of organic components within paint retards the durability and life span of paint due to the changing of appearance. Inorganic binders such as potassium silicate, sodium silicate, lithium silicate, and phosphate open the opportunity to replace organic binders that ensures the well-balance of functionality and durability. This study critically reviewed a variety of antimicrobial additives such as TiO2, Ag and ZnO nanomaterials and quaternary ammonium salts used in functional paints and coatings, as well as mechanisms of antimicrobial activities of TiO2-based materials. This paper also evaluated the strengths and drawbacks of antimicrobial, which then leads to the existing knowledge gap and the potential way forward.