中文摘要：

摘要以4-二甲氨基吡啶稳定的金纳米粒子（DMAP—AuNPs）为前驱体，通过与端基含二甲氨基查尔酮的聚N-异丙基丙烯酰胺（PNIPAM-DMAC）进行配体置换，制备了具有温度敏感和智能荧光特性的PNIPAM—DMAC聚合物包覆的金纳米粒子（PNIPAM—AuNPs），并通过紫外可见吸收光谱、透射微镜、核磁共振氢谱、红外光谱和热重分析仪对其形貌和结构进行了分析和表征．PNIPAM—AuNPs能够很好地分散在水、乙醇、丙酮、氯仿和四氢呋喃中，其表面等离子共振（SPR）吸收特征波长分别为537、527．6、527．4、532．2和530．4nm．PNIPAM—AuNPs的表面聚合物接枝密度为1～2条聚合物链／nm^2．温敏性结果表明，PNIPAM—AuNPs具有低临界溶解温度（LCST），其LCST温度比相应的PNIPAM—DMAC聚合物低2．5K；在PNIPAM—AuNPs发生相转变前后，金纳米粒子的SPR特征峰由537nm蓝移至525nm处．荧光性能研究表明，随着溶剂极性的增加，PNIPAM—AuNPs的荧光特征波长发生红移，荧光强度先增加后减小，具有极性敏感的荧光特性；在25℃时，PNIPAM—AuNPs水溶液几乎无荧光，而当温度升高到45℃后，荧光强度显著提高，表现出温度“开／关”的荧光特性．

英文摘要：

Polymer-coated gold nanoparticles （PNIPAM-AuNPs） with temperature sensitive and intelligent fluorescent properties were prepared by ligand exchange between dimethylaminochalcone-terminated poly （N- isopropylacrylamide） （PNIPAM-DMAC） and 4-dimethylaminopyridine-stabilized gold nanopartieles （DMAP- AuNPs） precursor,and the morphology and structure of the as-prepared AuNPs were analyzed by UV-Vis, TEM,IH-NMR,FTIR and TGA. The as-synthesized PNIPAM-AuNPs can be well dispersed not only in water but also in ethanol, acetone, chloroform and tetrahydrofuran, and the corresponding characteristic peak of the surface plasmon resonance （SPR） absorption of the PNIPAM-AuNPs is observed at 537 nm,527.6 nm,527.4 nm, 532.2 nm and 530.4 nm respectively. The surface grafting density of PNIPAM-DMAC is 1-2 polymer chains/nm2. The results of thermosensitive properties show that PNIPAM-AuNPs have a lower critical solution temperature （LCST） 2.5 K lower than that of PN1PAM-DMAC, and the SPR absorption peak of PNIPAM- AuNPs blueshifts to 525 nm from 537 nm after the phase transition. With the increase of the solvent polarity, the fluorescence characteristic wavelength of PNIPAM-AuNPs redshifls, and the fluorescence intensity first increases then decreases,which indicates solvent polarity sensitive fluorescence properties of PNIPAM-AuNPs. There are no fluorescent emitting properties of PNIPAM-AuNPs aqueous solution at 25 ℃ ,while at 45 ℃ the fluorescence intensity of PNIPAM-AuNPs enhances obviously,which endows PNIPAM-AuNPs with temperature ＂on/off＂ fluorescent properties.