Nanoporous Polymer Crystals with Cavities and Channels

Abstract

A cheap, commercial, and easy-to-process hydrocarbon polymer (syndiotactic polystyrene, s-PS) can be crystallized in two different nanoporous phases (δ and ε) that show large uptake of several guest molecules and hence are suitable for applications in chemical separations and air/water purification as well as in sensorics. The recently discovered ε phase of s-PS is characterized by channel-shaped cavities crossing the unit cells along the c axis rather than by isolated cavities as observed for the already known δ phase. Guest sorption from the δ and ε nanoporous phases eventually leads to two different classes of polymer cocrystals, where planar guest molecules present their planes roughly perpendicular and parallel to the polymer chain axes. The ε phase channels allow cocrystal formation with guest molecules much longer than the chain axis periodicity and, due to possible reactions between guest molecules, open the possibility to achieve new hybrid materials.