Microcapsules loaded with essential oil: Enhancing the hydrophobic and antifungal properties of wood-based panels

Natural anti-mildew agents are widely used in wood building materials because of its renewable and environmental protection characteristics. This study innovatively proposed a wood cell cavity to encapsulate plant essential oil for filling wood-based panels, aiming to enhance hydrophobicity and antifungal performance. Essential oil-esterophilic wood microcapsules (EO-EWM) were constructed with the strong natural barrier function of the wood cell walls to encapsulate fir essential oil in the cell cavity. The loading capacity of the essential oil in EO-EWM reached 695.3 mg/g, exhibiting outstanding slow-release properties, with a release rate of 59.9 % after 56 days of simulated release. The release mechanism followed the Fickian diffusion mechanism driven by concentration gradients. During the pressing process of the wood-based panel, the additional amount of EO-EWM was controlled within 30 % to ensure the mechanical properties of the panels. More importantly, the addition of EO-EWM significantly enhanced the self-cleaning capability and hydrophobic performance of the wood-based panels while the risk of mold growth on the panels reduced effectively. Essential oil wood-based panels (EO-WBP) exhibited effective antifungal of 75.0 % against Aspergillus niger and of 83.3 % against Penicillium citrinum. The main mechanism of the anti-mold was that the fir essential oil caused the distortion, shrinkage, and cracking of mycelium, thus inhibiting or killing mold. This study provides an effictive and environmentally friendly strategy for constructing hydrophobic and antifungal properties of wood-based panel for building materials.