Аннотация:A number of 22 polyheteroarylenes including 18 polyimides, divided in five series, were studied with regard to the dependence of permeability, diffusion and solubility coefficients of gases on the reverse value of fractional accessible volume. It was shown that all these dependences are linear in semilogarithmic coordinates. Thus, the overal selectivity, which is determined by the slope of these dependences, is correlated with the free volume in each series of polymers. The introduction of volumetric bridging groups into the diamine component with the possibility of rotation around bonds with the polymer backbone near the bridge leads to an increase in the overall selectivity of permeability, diffusion and solubility of the polymer at sufficiently high values of the permeability, diffusion and solubility coefficients.