Surface-energy characteristics of films of molecular brushes based on polyimide and poly(methyl methacrylate)

Surface characteristics of film samples of molecular brushes with a polyimide backbone and PMMA side chains, as well as of films of polyimide constituting the backbone and linear PMMA homopolymers obtained via the selective destruction of the polyimide backbone of these brushes, are investigated for the first time. The surface-energy characteristics of the films of molecular brushes are determined by the structure and conformational state of the PMMA side chains. The conformations of molecular brushes possessing a polyimide backbone well screened by side chains are preserved after the transition from solutions to “dry” copolymer films and are characterized by high stability. The observed surface activity of molecular brushes is due to adhesion interactions with functional groups of the substrate. The difference in surface activities is caused by small-scale conformational changes in the side chains of molecular brushes. A globular core of molecular brushes formed by the polyimide backbone remains practically spherical and probably does not change in volume.