An oriented self-standing film of zeolitic AFI crystal synthesized from an air-solution interface

在没有固体衬底的环境下，我们发现可以合成一种半透明的磷酸铝型微孔晶体AFI薄膜。为了阐明这一独特的合成过程，并利用这一发现来优化薄膜的合成条件，我们开发了一种静态水热合成系统，可以直接观察合成溶液的状态。乳白色的合成溶液在175℃的加热下粘度很高，合成溶液的上部出现一层透明的溶液，溶液的下部呈乳白色逐渐下降。在乳状部分下落过程中，薄膜的前驱体在透明层和乳状层的界面处形成。最后，薄膜在重力作用下落到反应容器的底部。

Under an environment of no solid substrate, we found a translucent free-standing film of alumino-phosphate type microporous crystal AFI could be synthesized. To elucidate this unique synthetic process and to utilize the discovery for optimizing synthetic conditions of the film, we developed a static hydrothermal synthesizing system that enables direct observation of the state of the synthetic solution.The milky colored synthetic solution has high viscosity under heating at 175 degrees C. A layer of transparent solution appears at the upper part of the synthetic solution and the milky lower part of the solution gradually comes down. During the falling of the milky part, a precursor of the film is formed at the interface of the transparent and milky layers. Finally, the film falls to the bottom of the reaction container by gravity.