Processing–Structure–Properties Relationships of Glycerol‑Plasticized Silk Films

This study systematically investigated how glycerol content governs the processing–structure–property relationships of regenerated silk fibroin films. By varying glycerol concentration from 0 to 30 wt%, the authors showed that low glycerol levels primarily plasticize amorphous domains through hydrogen bonding, while higher glycerol contents promote β-sheet formation and crystallinity. Mechanical testing revealed a dramatic transition from brittle behavior at low glycerol levels to highly stretchable and tough films at higher glycerol contents, with failure strains increasing from <3% to over 350%. These results clarify how glycerol regulates silk chain mobility, secondary structure formation, and macroscopic mechanical performance, providing design rules for tailoring silk-based thin films for flexible and biomedical applications.