Cover Image, Volume 136, Issue 45

The current image by Svetlana Viktorovna Kononova, Denis Sapegin, and colleagues represents phase heterogeneity between sulfonated polyimide and poly(amide-imide) polymer phases in the composite film with 7:3 polyimide to poly(amide-imide) weight ratio. Most likely, in this composite, a three-dimensional crystallizing network of polyimide is formed around poly(amide-imide) which is to form an amorphous phase. This assumption was confirmed by the data of the energy-dispersive analysis since it is in the region of the network structure sulfur atoms were detected, which are present in this composite only in the structure of sulfonated polyimide. DOI: 10.1002/app.48197