HYDRODYNAMIC AND CONFORMATIONAL PROPERTIES OF POLYNAPHTHOYLENEBENZIMIDAZOLE MOLECULES IN SOLUTION.

The coefficients of translational diffusion D and intrinsic viscosity ( eta ) of seven samples of polynaphthoylenebenzimidazole have been measured in sulphuric acid. From the experimental ( eta ) and D values, the molecular masses M//D// nu have been calculated for various values of the hydrodynamic invariant A//o and equations relating ( eta ) and D with M//D// nu have been derived. The length of the Kuhn segment, A equals ca. 5. 0 nm has been determined from the hydrodynamic data. The molecules of the polymer being studied were shown to be in the conformation of an hydrodynamically impermeable Gaussian coil. The possible mechanisms of molecular chain flexing were discussed for various configurations of the naphthoylenebenzimidazole group.