Structure of comblike polyimide prepolymer solutions

The viscometry and light scattering techniques and the Debye-Stein statisti cal theory were applied to study the structure of amphiphilic polyimide pre polymers and variation of the structure with time in a mixed dimethylacetam ide-benzene solvent. The solutions of dimethylhexadecylamine salt of the po ly(amic acid) based on 3,3',4,4'-biphenyltetracarboxylic dianhydride and o- tolidine were studied. These solutions are used for casting the Langmuir-Bl odgett films. It was shown that, in going from the poly(amic acid) to its a mmonium salt, the intrinsic viscosity and, therefore, the hydrodynamic size s of a macromolecular coil decrease. In dilute solutions of the salt in a d imethylacetamide-benzene mixture, supramolecular associates of the fluctuat ion nature were revealed. On storage, these solutions undergo structural se lf-organization which is displayed as a considerable increase in the soluti on microheterogeneity and local ordering.