A facile method to fabricate syndiotactic polystyrene aerogels by freeze-drying

A facile method has been developed to produce syndiotactic polystyrene (sPS) aerogels by only three steps of polymer dissolution, gel aging and freeze-drying without any solvent exchange, unlike typical methods for sPS aerogel preparation. Due to the high melting point of <i>p</i>-xylene (around 13 °C), <i>p</i>-xylene-based sPS gels are unexpectedly robust in allowing the formation of aerogels by direct <i>p</i>-xylene removal through sublimation, leading to a more efficient synthesis and better quality of aerogels with much stronger mechanical properties. Furthermore, without the interference of solvent exchange, it is more suitable to explore the influence of key parameters (sPS content and molecular weight in precursor gels) on the preparation of sPS aerogels. The content and molecular weight of sPS will affect the crystallinity and porosity of the sPS aerogels, which can further control the microstructure, mechanical properties, dielectric constant, and adsorption performance of the materials. The obtained low density sPS aerogels with 98.9% porosity exhibited a minimum dielectric constant of 1.02 at low frequencies and high adsorption capacity towards different organic solvents and common oil.