Non-covalent synthesis of thermo-responsive graphene oxide–perylene bisimides-containing poly(N-isopropylacrylamide) hybrid for organic pigment removal

•Thermo-responsive graphene oxide is synthesized via non-covalent interactions.•The material exhibits temperature-controllable assembly and disassembly behaviors.•The graphene oxide can work as an efficient adsorbent for methylene blue removal.•The adsorbent can be easily removed by filtration after the adsorption process.

In this work, thermo-responsive graphene oxide–perylene bisimides-containing poly(N-isopropylacrylamide) hybrid (TGO) was successfully prepared via non-covalent π–π stacking interactions of GO and perylene bisimides-containing poly(N-isopropylacrylamide) (PBI-PNIPAM). PBI-PNIPAM was synthesized by atom transfer radical polymerization of N-isopropylacrylamide, using bifunctional N,N′-bis[6-(2-chloropropionamide)hexyl] perylene-3,4,9,10-tetracarboxylic acid bisimide (PBI-Cl) as the initiator. The obtained polymer was then characterized by 1H NMR and fluorescence spectroscopy. The surface chemical states, morphology, and composition of TGO were characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), respectively. This new hybrid showed reversible temperature-dependent self-assembly and disassembly at 35.9 °C in water. Therefore, it may have great potentials as a convenient adsorbent for removing organic pigment, as exemplified as for removing methylene blue from water with excellent adsorption capacity of 568 mg/g, high removal efficiency of 99.5%, and facile temperature-controlled post-separation of the adsorbent.

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