Porous Polymer Structures for Trapping Solvent Molecules

Syndiotactic polystyrene (sPS) is liable to produce polymer-solvent compounds with a large variety or organic solvents. The solvent molecules can be removed while keeping the original crystalline lattice unchanged, thus producing emptied chlathrates which are nanoporous and possess the propensity of absorbing again solvent molecules in water even to very low amounts. So far these materials were obtained as powders. Here it is shown how membranes possessing both subnanoporosity and microporosity can be prepared. Several approaches have been used: gel formation5 or exposure of the solid sPS to liquid or vapour solvent. These polymer membranes might be of interest for ultrafiltation processes used in water purification. The thermodynamic of preparation of such systems as well as their structure and morphology are discussed.