3. Results and discussion
The fabrication process of the composite film is illustrated inFig. 1 . First, MMT colloid was obtained after sonication of MMT
in water,[34] then mixed with PAAS solution. The
resulting glue has a brown color, and no precipitation is generated
because of the interaction between them, especially the interaction of
hydrogen bond. Finally, the glue was poured onto the PI film fixed by
the flange ring and put into the temperature-controlled oven. At lower
temperature, MMT nanosheets adhered to PAAS gradually precipitated to
the bottom under the action of gravity (because of the large aspect
ratio of MMT) and were well arranged in a “flat lay” manner. thermal
imidization was completed to obtain the final composite film.