Structure of Silicon-Substituted Polytricyclononene Films: Small-Angle Neutron Scattering Data

Abstract

Polytricyclononenes are new polymers having high permeability values not only for atmospheric gases, but also gaseous hydrocarbons. Thin films (≤100 μm) used in gas-separation membrane technologies are necessary to be studied to improve the gas transport properties of these polymers. The structure of polytricyclononene films with two vicinal side substituents Si(CH₃)₃ in a monomer unit synthesized via additive polymerization scheme is studied in this work by a small-angle neutron scattering method. As a whole, the amorphous film has a local orientation order due to chain fragments with spiral conformation. The size of the ordered regions is comparable to the length of units correlations in the polymer chain (Kuhn segment) and is 8–9 nm. Free volume and type of voids (pores) formed in the polymer film due to inhomogeneous packing are also found.