Inhomogeneity in the drying process of gelatin film formation: NMR microscopy and relaxation study

Gelatin film formation was investigated in situ during evaporation of the solvent. Gelatin was dissolved in deuterium oxide (D2O) at 50 °C followed by casting. The drying process of the gelatin–D2O solution system was observed using a single-sided NMR scanner by application of the Carr–Purcell–Meiboom–Gill (CPMG) pulse sequence at different layer positions. The echo decays were analysed and spin–spin relaxation times (T2) were obtained for each layer. It was found that the drying process for the film formation occurs in a stratified fashion.