Copolymer networks with contorted units and highly polar groups for ultra-fast selective cationic dye adsorption and iodine uptake

Three organic copolymer networks CP1-3 were synthesized using a mild polycondensation reaction of the commercially available tetrafluoroterephthalonitrile with three different building blocks with contorted geometries and bearing two hydroxyl groups, namely, triptycene 1a, fluorescein 1b, and phenolphthalein 1c. The target cross-linked copolymers CP1-3 revealed ultra-fast uptake of the cationic dye methylene blue (MB) with an adsorption capacity reaching 300 mg/g. In addition, selectivity studies proved the preference of CP2 towards the cationic dye MB over the anionic dyes, such as, methyl orange (MO) and Congo red (CR). Copolymers CP1-3 also show superior iodine uptake properties reaching ∼150 wt% with virtually no loss in the adsorption capacity even after several successive adsorption-desorption cycles. The easy preparation and promising dyes adsorption and iodine uptake capacities promote the contorted copolymers CP1-3 as promising materials for environmental remediation applications.