Department of Technical Physics II/Polymer Physics, Institute of Physics, Faculty of Mathematics and Natural Science, Ilmenau University of Technology, P.O. Box 10 05 65, D-98684 Ilmenau, Germany.
J Phys Chem B. 2010 Dec 16;114(49):16356-63. doi: 10.1021/jp1068363. Epub 2010 Nov 18.
Gelatin solutions were prepared in D(2)O. The drying process of cast solutions was followed with a single-sided nuclear magnetic resonance (NMR) scanner until complete solidification occurred. Spin-spin relaxation times (T(2)) were measured at different layers with microscopic resolution and were correlated with the drying process during film formation. Additionally, the evaporation of the gelatin solution was observed optically from the reduction of the sample thickness, revealing that at the macroscopic level, the rate of evaporation is not uniform throughout the experiment. A crossover in the spatial evolution of the drying process is observed from the NMR results. At the early stages, the gel appears to be drier in the upper layers near the evaporation front, while this tendency is inverted at the later stages, when drying is faster from the bottom. XRD (X-ray diffraction) data showed that a structural heterogeneity persists in the final film.
明胶溶液在 D(2)O 中制备。采用单面核磁共振（NMR）扫描仪跟踪铸液的干燥过程，直至完全凝固。在不同层以微观分辨率测量自旋-自旋弛豫时间（T(2)），并将其与成膜过程中的干燥过程相关联。此外，通过观察样品厚度的减少，可以从光学上观察明胶溶液的蒸发，表明在宏观水平上，蒸发速率在整个实验过程中并不均匀。从 NMR 结果可以观察到干燥过程空间演化的交叉。在早期阶段，凝胶在靠近蒸发前沿的上层似乎更干燥，而在后期阶段，当底部干燥更快时，这种趋势会反转。XRD（X 射线衍射）数据表明，在最终薄膜中存在结构不均匀性。
