Structure-Dynamics-Property Relationships in Silk Fibroin Films Probed via Solid-State NMR

Silk fibroin films offer tunable mechanical properties, yet the structural origins of this tunability are incompletely understood. Here, we show how solvent choice and post-treatment govern the mechanics of silk fibroin films by combining solid-state NMR relaxation measurements (13C T1/T1ρ; 1H T1/T1ρ), X-ray diffraction, and TG-DTA analyses. Formic acid-derived films exhibited a 6-fold higher Silk II content and greater backbone constraint (longer 13C T1ρ) than water-derived films, resulting in