Crosslinked siloxane–silsesquioxane elastomer with pyrene functionalization for rapid adsorption of benzene, toluene, and xylene (BTX) from water and sensing of charged species

Abstract

A crosslinked siloxane/silsesquioxane elastomer with pyrene functionalization (Py-CSSE) was rapidly synthesised within 10 minutes via a one-pot multicomponent anionic ring-opening polymerization between octamethylcyclotetrasiloxane (methyl D₄), octavinylsilsesquioxane (OVS) and a mono-pyrene functionalized SQ cage (Mono-PySQ). The structural characterization of Py-CSSE was conducted using MAS solid-state ²⁹Si and ¹³C NMR, FTIR, and PXRD techniques. Furthermore, an examination of the mechanical and thermal characteristics was conducted using TGA, DSC, and compressive tests. Py-CSSE demonstrated significant elasticity (a strain of 60% and a pressure of 0.5 MPa) and quickly returned to its former shape without any cracking, even when subjected to a pressure range of up to 40% strain for 3 cycles. The pyrenyl moieties permitted a strong blue fluorescence emission in both the solid-state and in suspension in an organic solvent. The presence of silsesquioxanes, siloxanes, and pyrene moieties concomitantly facilitated its use in cation (Cu²⁺) and anion (F⁻ and CN⁻) sensing in polar organic solvents. Importantly, Py-CSSE exhibited efficient adsorption of benzene, toluene, and xylene (BTX) by showing a remarkably high adsorption capacity in the range 28–34 mmol g⁻¹. Py-CSSE exhibited ultrafast adsorption of BTX by showing complete removal of o-xylene within 90 seconds. Furthermore, Py-CSSE surpassed other porous materials in terms of BTX adsorption performance and showed exceptional recyclability for BTX removal, maintaining adsorption effectiveness for at least 5 cycles.