Cationic Fluorinated Polyphosphazenes for Efficient Decontamination of Anionic Pollutants from Wastewater

This work presents a simple and efficient methodology for the synthesis of well-defined fluorinated copolyphosphazenes incorporating 2,2,2-trifluoroethan-1-olate (–OCH2CF3, TFE) and 3-(diethylamino)phenolate (3DEAP) side groups, randomly distributed along the polymer chains, via living cationic polymerization. Two fluorinated copolyphosphazenes, 4a and 4b, with different CF3/3DEAP ratios (1:1 and 1:3, respectively), are prepared. The 3DEAP groups in these polymers are selectively and smoothly quaternized using methyl iodide (CH3I), yielding cationic fluorinated copolyphosphazenes 5a and 5b with quaternization degrees of ≈80% and 90%, respectively. These cationic copolymers, featuring tailored CF3/3DEMAP+ ratios (3DEMAP+ = 3-(diethyl(methyl)ammonio)phenolate), exhibit complete water solubility and demonstrate self-assembly in aqueous solutions, forming large compound micelles (LCMs) or bilayer vesicles depending on their composition. The amphiphilic nature of these materials, combining hydrophobic (CF3) and hydrophilic (3DEMAP+) moieties, enables their application in the efficient capture of anionic pollutants, such as sodium diclofenac (SDF) and perfluorooctanoic acid (PFOA), commonly found in wastewater. This study highlights the potential of these cationic fluorinated copolyphosphazenes as promising candidates for water decontamination and environmental remediation.