*3.5. Oxygen and Water Vapor Permeability*

Permeability tests were performed using a PERME TM OX2/231 Permeability Tester from Labthink Instruments Co., Ltd. (Jinan, China), using oxygen as the test gas (RH 50%) at a temperature of 18 ± 2 ◦C. Nitrogen was used as the oxygen carrier. The oxygen flow rate was fixed at 20 mL/min, while that of nitrogen was 10 mL/min. The WVPs of the films were determined by a Perme VAC-V1 (Labthink, Jinan, China) at 18 ± 2 ◦C and 60% RH.
