Preparation of temperature-responsive nanomicelles with AIE property as fluorescence probe for detection of Fe3+ and Fe2+

Temperature-responsive nanomicelles with aggregation induced emission (AIE) property were prepared by the host-guest complexation of ferrocene functionalized tetraphenyl (TPE-Fc) and β-cyclodextrin-poly (N-isopropylacrylamide) (β-CD-(PNIPAM)7). The AIE chromophore TPE-Fc bound to the hydrophobic cavity of cyclodextrin serves as the core of micelles, and temperature sensitive PNIPAM serves as the shell to give the micelles good solubility. The size of the nanomicelles is about 100 nm. At the excitation wavelength of 340 nm, the strongest fluorescent emission peak was 421 nm. The introduction of cyclodextrin star polymer increased the fluorescence intensity of nanomicelles, thus improving the recognition of probe to Fe3+ and Fe2+. The fluorescent probe can quickly detect Fe3+ and Fe2+ in water within 5 min even in the presence of various interfering ions. The detection limits of Fe3+ and Fe2+ were 1.04 μM and 0.78 μM, respectively in the range of 10-90 μM. The formation of complex between the probe and Fe3+/Fe2+ was supported by Job's plot. The probe was successfully applied to the detection of Fe3+and Fe2+ in actual water sample with a good recovery. In addition, a possible sensing mechanism for the interaction of iron ions with amide bond groups of nanomicelles was proposed.