Preparation And Performance Of Multi-Functional Molecularly Imprinted Polymer With Reversible Addition-Fragmentation Chain Transfer Polymerization

Molecular imprinting is a highly accepted synthesis approach for the preparation of tailor-made recognition material with cavities that are able to selectively recognize target molecules. The molecular imprinted polymers boast the characters of prearrangement, recognition and selectivity. In this work, we have prepared multifunctional molecularly imprinted polymers with superparamagnetism, excellent fluorescent properties and fast transportation rate on different supportings such as silica gels, Fe3O4 functionalized silica gels, magnetic/optical silica gels and graphene oxide by combining reversible addition-fragmentation chain transfer (RAFT) polymerization approach and molecular imprinting technology. The resulting composites were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) photoluminescence (PL) spectra, fourier transform infrared (FT-IR) analysis, vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA) and BET adsorption isotherm analysis. The mechanism of their selectivity for EDCs in water was also investigated.The super-thin surface-imprinted core-shell magnetic molecular imprinted nanobeads were prepared with spherical silica as the support. Absorption experiments demonstrated linearized pseudo second-order kinetic model, in good agreement with Langmuir absorption isotherm. The imprinted nanobeads showed strong affinity and excellent selectivity. Density functional theory calculations verified the mechanism of selectivity and recognition of these imprinted nanobeads.Molecular imprinted nanobeads with core-shell structure were prepared with Fe3O4@SiO2 as the supporting. The homogeneous polymer films had the thickness of about 22 nm. The as-synthesized surface-imprinted core-shell magnetic beads showed outstanding affinity and selectivity over other structurally related compounds and the resulting composites reusability without obviously deterioration in performance was demonstrated at least five repeated cycles. In addition, the system can be easily separated under an external magnetic field.Molecular imprinted nanobeads with core-shell structure were prepared with magnetic Fe3O4@SiO2-Dye-SiO2 as the supporting. The polymer and FITC layer of Fe3O4@SiO2-MIP had the thickness of about 5.7 nm and 8.7 nm, respectively. The limit of detection is 0.19μmol/L measuraed by photoluminescence spectrometer and the beads can be reused for at least up to 5 times without significant loss of magnetic moment and signal intensity. In addition, the Stem-volmer equations illustrated the mechanism of fluorescent quenching. A molecularly imprinted polymer–graphene oxide (MIP-GO) hybrid material was synthesized with graphene oxide as the support. The average thickness of the polymer grafted on the GO surface is about 3.707 nm. Adsorption experiments demonstrated that the hybrid material has strong affinity, excellent selectivity and reusability. Density functional theory calculations verified that the substrate provides a significantπsurface that could overlap with theπorbitals of 2,4-DCP and obtains stability through electrostatic interaction, resulting in the formation ofπ-πstacking, and the mechanism of the significant improvements on the affinity and selectivity of the MIP-functionalized graphene materials.