Near-infrared-emitting silsesquioxane-based porous polymer containing thiophene for highly efficient adsorption and detection of iodine vapor and solution phase

Abstract

The powerful gathering and potent detection of radioactive iodine, which may be created during the production of nuclear energy or the management of nuclear waste, are essential. Herein, near-infrared-emitting (NIR) porous polymeric materials with thiophene (PCS-DPBS) were employed for the first time to capture iodine vapor effectively and reversibly. The fluorophore monomer (CN-DPBS) with a donor–acceptor-donor (D-A-D) typed electronic configuration exhibiting near-infrared fluorescence emission was successfully produced by the Knoevenagel reaction. Then, CN-DPBS reacted with octavinylsilsesquioxane (OVS) via the Friedel-Crafts reaction, resulting in a series of porous polymers based on silsesquioxane (PCS-DPBS). The polymer was effectively synthesized, as evidenced by elemental analysis, FT-IR, solid-state 29Si NMR, and solid-state 13C NMR spectra. The morphology of PCS-DPBS was also demonstrated by XRD and SEM results. Interestingly, the resulting polymer has distinct properties and characteristics such as NIR emission (663 nm), adjustable porosity (specific surface area of 245 m2 g−1 and total pore volumes of 0.150 cm3 g−1), and thermal stability with Td5% and Td10% of 202 and 414 °C, respectively, in N2 atmosphere. With a large micropore volume and a high thiophene content in its polymer structure, this results in high iodine vapor adsorption capacities, with uptake capacities up to 2.81 g g−1 at 70 °C. The recycling ability is at least five times and the iodine uptake capacity is still >50%. The CN-DPBSunit provides PCS-DPBS with unique luminescence, allowing it to function as a probe to detect iodine solution with great sensitivity with KSV values of 1622.4 M−1. This study on a thiophene-containing adsorbent brings up new possibilities for the effective capture and detection of iodine in environment.