Syndiotatic Polystyrene Aerogels with β, γ, and ε Crystalline Phases

The influence of thermal treatments and supercritical carbon dioxide extraction procedures on the crystal structure and morphology of sPS aerogels is investigated mainly by wide-angle X-ray diffraction and scanning electron microscopy. The use of supercritical CO 2 extraction treatments allows the obtaining of high porosity aerogels with fibrillar morphology, not only exhibiting the nanoporous δ phase but also the dense γ and β crystalline phases. Moreover, a procedure to obtain high-porosity aerogels exhibiting the recently discovered nanoporous ε-form is described. Measurements of the sorption capacity of organic molecules from diluted aqueous solutions, for aerogels presenting different crystalline phases, clearly indicate that ε-form aerogels are the only ones suitable for detection and removal of long organic pollutants.