Introducing Polyhydroxyurethane Hydrogels and Coatings for Formaldehyde Capture

Formaldehyde (FA) is a harmful chemical product largely used for producing resins found in our living spaces. Residual FA that leaches out the resin contributes to our indoor air pollution and causes some important health issues. Systems able to capture this volatile organic compound are highly desirable; however, traditional adsorbents are most often restricted to air filtration systems. Herein, we report novel waterborne coatings that are acting as a FA sponge for indoor air decontamination. These coatings, of the poly(hydroxyurethane) (PHU) type, rich in primary amine groups, are prepared by the polyaddition of a hydrosoluble dicyclic carbonate to a polyamine in water at room temperature under catalyst-free conditions. We highlight the importance of the choice of the polyamine on the curing rate of the formulation and on the FA capture ability of PHU. The excellent FA capturing ability of the best candidate is rationalized by investigating the action mode of the polyamine used to construct PHUs. With poly(vinyl amine), FA is covalently and permanently bound to PHU, with no release over time. The performance of the coating in FA abatement is impressive, with more than 90% of captured FA after one day of contact. The facility to prepare these transparent and colorless coatings from waterborne formulations gives access to new efficient indoor air depolluting solutions, potentially applicable to various surfaces of our living spaces (wall, ceiling, etc.).