Investigation of he gas permeation parameters of several polyetherimides and polymers of intrinsic microporosity showed that their properties (permeability and permselecitivity) are sensitive to the presence of low molecular mass compounds (chloroform, lower alcohols, water) that are capable of forming hydrogen bonds. Using the FTIR method and quantum chemical calculations, it was shown that such bonds are formed and they induce structural (conformation) changes in the polymer matrices. Other types of weak interactions, dipole dipole interactions, are responsible for unusual sorption behavior of acetone in amorphous Teflon AF2400. Therefore, intermolecular interactions can influence transport and sorption properties of glassy membrane materials.