Eco-Friendly, High-Performance Cellulose Acetate Encapsulation for Flexible Hybrid Electronics: Environmental Stability and Printing Scalability

In this study, we developed a screen-printable, cost-effective, biocompatible, and biodegradable dielectric ink based on cellulose acetate for encapsulating biomedical electronic device packaging. To evaluate its environmental stability, the encapsulated samples were subjected to accelerated aging conditions of 70 °C and 80% relative humidity for 216 hours. Three groups were tested: non-encapsulated controls, cellulose acetate-encapsulated samples, and samples encapsulated with a commercial material (Micromax ME778). Sheet resistivity was measured before and after environmental aging to assess the protective performance of each encapsulant. The cellulose acetate-encapsulated samples exhibited only an 11.8% increase in sheet resistivity, compared with a significant 65.6% increase observed in the ME778 group. These results demonstrate the superior environmental protection and suitability of cellulose acetate as a sustainable encapsulant for printed biomedical electronics.