Property variation of ionic liquid [Bmim][AuCl_4] immobilized on carboxylated polystyrene submicrospheres with a small surface area  

作　　者：HE YaXing FU HaiYing LI Cheng JI Xiang GE XueWu ZOU Yang JIANG Zheng XU HongJie WU GuoZhong 

机构地区：[1]Shanghai Institute of Applied Physics, Chinese Academy of Sciences [2]Graduate University of Chinese Academy of Sciences [3]Chinese Academy of Sciences Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China

出　　处：《Chinese Science Bulletin》2013年第24期2950-2955,共6页

基　　金：supported by the National Natural Science Foundation of China (11079007, 51073146, 51103143, 11005148, 20973192 and 10705046)

摘　　要：In order to understand the effect of surface chemical groups on the immobilized species, Au-containing imidazolium-based ionic liquid (IL) [Bmim][AuCl4] was intentionally immobilized on polystyrene (PS) submicrospheres (d～300 nm) with a very small surface area (4-10 m2/g), which possess carboxyl-moiety (COONa or COOH) on the surface. The behavior of immobilized [Bmim][AuCl4 ] on the two types of submicrospheres was investigated by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and powder X-ray diffraction (XRD). It was revealed that the melting points (Tm) of [Bmim][AuCl4 ] that had been immobilized on PS-COONa and PS-COOH submicrospheres were decreased by 2.7 and 4.1℃, respectively. The interaction mechanism between the IL and submicrosphere surface moieties was further analyzed by X-ray absorption fine structure (XAFS) analysis. The data indicated that the coordination environment of Au species changed markedly when [Bmim] [AuCl4] was immobilized on the surfaces of PS-COONa and PS-COOH submicrospheres, as illustrated by the decrease in white line peak intensity. The effect of surface COOH groups on Tm depression and the white line peak intensity of the XANES spectrum is more pronounced than that of COONa groups, most likely due to the possible hydrogen bond formation between the COOH group and [Bmim]+.In order to understand the effect of surface chemical groups on the immobilized species, Au-containing imidazolium-based ionic liquid （IL） [Bmim][AuCl4] was intentionally immobilized on polystyrene （PS） submicrospheres （d-300 nm） with a very small surface area （4-10 m2/g）, which possess carboxyl-moiety （COONa or COOH） on the surface. The behavior of immobilized [Bmim][AuCl4] on the two types of submicrospheres was investigated by transmission electron microscopy （TEM）, differential scanning calorimetry （DSC）, and powder X-ray diffraction （XRD）. It was revealed that the melting points （Tin） of [Bmim][AuC14] that had been immobilized on PS-COONa and PS-COOH submicrospheres were decreased by 2.7 and 4.1℃, respectively. The interaction mechanism between the IL and submicrosphere surface moieties was further analyzed by X-ray absorption fine struc- ture （XAFS） analysis. The data indicated that the coordination environment of Au species changed markedly when [Bmim] [AuCl4] was immobilized on the surfaces of PS-COONa and PS-COOH submicrospheres, as illustrated by the decrease in white line peak intensity. The effect of surface COOH groups on Tm depression and the white line peak intensity of the XANES spec- trum is more pronounced than that of COONa groups, most likely due to the possible hydrogen bond formation between the COOH group and [Bmim]＋.

关 键 词：离子液体 聚苯乙烯 表面积 羧基 X射线吸收精细结构 差示扫描量热法 化学基团 变异 

分 类 号：O631.3[理学—高分子化学]