Study on the Characteristics of Gelatin-based Film Precursor Solution Prepared Using a Deep Eutectic Solvent

Using gelatin as the raw material, a homogeneous solution was prepared by dissolving it in a ternary system of sodium acetate trihydrate/urea/water (DES/H₂O). Compared to traditional water system, gelatin dissolved by DES/H₂O can expose more active functional groups. Therefore, more ester bonds could be formed between gelatin and polyvinyl alcohol when using carbon diimide hydrochloride as a cross-linking agent. Results indicate that, when DES/H₂O solvent contained 60% DES was used (based on the total mass of the DES/H₂O solution), the prepared gelatin-based film precursor exhibited 95.23% of transmittance, 1 524.0 nm of particle size, and -31 ℃ of crystallization temperature. At a shear rate of 10 s^-1, its viscosity was 449.07 mPa·s. These findings suggest that the prepared gelatin-based precursor solution demonstrates strong cross-linking effect, good compatibility, and stable internal structure, providing a novel method for processing gelatin-based films with favorable physicochemical properties.