Formation and Growth Mechanism of Ceftezole Sodium Monohydrate Ring-Banded Spherulites

Abstract

In this study, ring-banded spherulite films of ceftezole sodium monohydrate were obtained by evaporating droplets on a glass sheet. The formation of ring bands was analyzed in detail by using a scanning electron microscope and atomic force microscope. The evolution process of spherulites was monitored by intermittent sampling, and the results showed that the formation of ring bands was controlled by material transport. Furthermore, the additive gelatin was selected to construct a diffusion-limited system, in which the spherulites can be changed from radial growth to concentric ring-banded growth by slowing down the evaporation rate. The intermittently changing lamellae stacking mode of ring bands indicates that the lamellae are twisted due to the influences of various types of stress. Finally, a reasonable growth mechanism of ring-banded spherulites was proposed to reveal the assembly process of the hierarchical structure.