Preparation of covalent organic framework-based nanofibrous films with temperature-responsive release of thymol for active food packaging

Thymol (THY) is commonly used in active food packaging, however because of its high volatility, poor water solubility, and strong aromatic odor, the application of THY is facing challenges. Herein, covalent organic frameworks (COFs) were synthesized in room temperature by asymmetric monomer exchange method for THY encapsulation, and solution blow spinning was used to fabricate the THY@COF/polycaprolactone (PCL) nano-fibrous films. The synthesized COFs had a large specific surface area, porous structure, and loading capacity of 30.35% for THY, and THY@COFs possessed good thermal stability. Characterization analysis showed that THY@COFs were successfully incorporated into the PCL films and increased the barrier property of the films. Besides, the films showed good biocompatibility and antibacterial activity. Moreover, THY@COF/PCL films exhibited temperature-responsive THY release profiles, which is important for practical preservation applica-tions, especially for preserving food in warm environments. Overall, THY@COF/PCL films possess promising potential in active food packaging.

Automated summary

In this study, covalent organic frameworks (COFs) were synthesized at room temperature using the asymmetric monomer exchange method for thymol (THY) encapsulation. The THY@COF was incorporated into polycaprolactone (PCL) nano-fibrous films using solution blow spinning technique. The synthesized COFs exhibited a porous structure, large specific surface area, and a loading capacity of 30.35% for THY, while THY@COFs showed good thermal stability. The characterization analysis confirmed the successful incorporation of THY@COFs into the PCL films, resulting in increased barrier properties, biocompatibility, antibacterial activity, and temperature-responsive THY release profiles.