Abstract: Chloromethylation reaction of polysulfone(PSF) was performed with 1,4-bis(chloromethoxy)butane(BCMB) as chloromethylation reagent,leading to the formation of chloromethylated polysulfone(CMPSF).Subsequently,the nucleophilic substitution reaction between the chloromethyl group of CMPSF and phenolic hydroxyl group of 6-hydroxy-2-naphthoic acid(HNA) was performed,and the ligand of naphthoic acid(NA) was bonded on the side chains of polysulfone,resulting in naphthoic acid-functionalized polysulfone NAPSF.The chemical structure of NAPSF was characterized by FTIR and ¹H NMR spectroscopies.The effects of the main factors on the nucleophilic substitution reaction between CMPSF and HNA were examined,the reaction mechanism was investigated,and the reaction conditions were optimized.Results show that the rate of the nucleophilic substitution reaction is independent of the concentration of the nucleophile HNA,indicating that this is a typical unimolecular nucleophilic substitution reaction,i.e.,S_N1.The solvent polarity is favorable for the cleavage of C-Cl bond of the benzyl chloride group,and can accelerate the substitution reaction.Therefore,dimethylsulfoxide(DMSO) with stronger polarity is a suitable solvent.Under the suitable conditions,the conversion of chloromethyl group of CMPSF can reach 96%,and the corresponding bonding degree of NA is 1.68 mmol/g.The coordination reaction between NAPSF and Eu³⁺ ion was carried out for preparing the polymer-rare earth complex of NAPSF-Eu(Ⅲ),which exhibited the characteristic fluorescence emission spectrum of Eu³⁺ ion.More significantly,the macromolecular ligand NAPSF can strongly sensitize the fluorescence-emission of Eu³⁺ ion.