Preparation of humidity- and temperature-responsive cinnamon essential oil microcapsules for wood protection

Cinnamon essential oil microcapsules were fabricated via complex coacervation using gelatin and acacia gum. The microcapsules were spherical and smooth, with an average size of 2.67 ± 0.84 μm, enabling efficient penetration into poplar wood ( Populus tomentosa Carrière) vessels. Microencapsulation reduced the volatilization of CEO, endowing the system with sustained-release performance. The gelatin–acacia gum shell exhibited humidity- and temperature-dependent swelling, resulting in increased porosity and accelerated CEO release under conditions favorable for mold growth. The release behavior followed the Avrami model, reflecting a transition between diffusion-controlled and first-order kinetics, indicating a combined mechanism of diffusion and structural evolution of the capsule wall. The microcapsules showed antifungal activity against Aspergillus niger , Trichoderma viride , and Penicillium citrinum . Due to their responsive release behavior and retention within wood, the treated samples exhibited enhanced mold resistance. These findings highlight the potential of natural polymer-based microcapsule systems as sustainable and responsive antifungal solutions for wood protection. • CEO microcapsules were fabricated by complex coacervation using gelatin–AG. • Spherical microcapsules penetrated poplar vessels effectively. • Hydrogen bonding helped retain microcapsules within the wood matrix. • Release was temperature- and humidity-dependent and followed Avrami kinetics. • Treated wood showed strong antifungal resistance to common mold strains.