Syndiotactic Polystyrene Films with Sulfonated Amorphous Phase and Nanoporous Crystalline Phase

Abstract

A solid-state sulfonation procedure on syndiotactic polystyrene (s-PS) δ-form films allows an easy and uniform sulfonation of the phenyl rings of the amorphous phase and preserves the nanoporous δ-phase. The high degree of sulfonation of the amorphous phase (up to a molar ratio 2/1 between phenyl rings and sulfonic groups) makes this phase highly hydrophilic, whereas the hydrophobic crystalline phase maintains its guest sorption ability. s-PS films, sulfonated only in the amorphous phase and exhibiting the nanoporous δ-phase, present kinetics of guest sorption from water solutions into the crystalline phase, being markedly higher than those of the corresponding unsulfonated films. For instance, DCE sorption kinetics from 50 ppm aqueous solutions show an unaltered DCE equilibrium uptake (close to 4 wt %) associated with a DCE diffusivity increase of more than 70 times. Moreover, the nanoporous crystalline phase and its sorption ability remain essentially unaffected by water sorption/desorption cycles. The reported results hence indicate that these new materials are particularly suitable for removal of VOC pollutants from water and moist air.

Monolithic Nanoporous Crystalline Aerogels

“…The number of possible applications can be further increased by suitable functionalization of the polymeric amorphous phase of the aerogels . Just as an example, the solid‐state sulfonation procedure on s‐PS films could be extended to aerogels making the amorphous cavities hydrophilic while maintaining the hydrophobicity of the crystalline cavities.…”

Sulfonated syndiotactic polystyrene: sorption of ionic liquid in the amorphous phase and of organic guests in the crystalline phase

“…Sulfonated films were achieved by using a procedure described by Borriello et al . and G. Fasano et al…”

“…However, the presence of a hydrophobic crystalline phase makes crystallinity and related physical properties essentially independent of water sorption/desorption cycles. s‐PS films, sulfonated only in the amorphous phase and exhibiting the nanoporous δ phase, present kinetics of guest sorption from water solutions being markedly higher than those of the corresponding unsulfonated films, which are already extremely efficient in removal of VOC from water …”

Nanoporous Semicrystalline Syndiotactic Polystyrene with Sulfonated Amorphous Phase, for a Fast and Efficient Removal of VOC Pollutant Traces From Water

“…This strongly reduces pollutant sorption kinetics from water and constitutes a major drawback for their practical use in water purification. This inconvenience can be overcome by a selective solid‐state sulfonation procedure of the amorphous phase . This leaves essentially unaltered the nanoporous‐crystalline phases while making highly hydrophilic the amorphous phase.…”

“…This inconvenience can be overcome by a selective solid-state sulfonation procedure of the amorphous phase. [12] This leaves essentially unaltered the nanoporous-crystalline phases while making highly hydrophilic the amorphous phase.…”