Structural Characterization of Polymers of Intrinsic Microporosity Using X-ray Scattering Methods*

Polymers of intrinsic microporosity (PIMs) are a novel class of materials with a large inner surface area and large free volume, which make them suitable for hydrogen adsorption. In addition, they exhibit a combination of high permeability and high selectivity useful for filtration applications. A series of polymers with high glass transition temperatures based on PIM-1, a polybenzodioxane with a ladder-type structure combining stiff segments with sites of contortion, as well as a series of triptycene-based network PIMs, are characterized via small-angle and wide-angle X-ray scattering. Scattering features, including multiple amorphous halos and a characteristic power-law slope, are related to polymer chemistry, hydrogen adsorption performance, and gas permeation parameters.