铁磁性导电聚苯胺—钴或铁的合成与表征

【作者】 汤力；

【导师】 阚锦晴；

【作者基本信息】 扬州大学 ， 物理化学， 2009， 硕士

【摘要】 在室温下,含有适量过渡金属离子(氯化钴或氯化铁)的苯胺(0.1 mol dm-3)与盐酸(0.5 mol dm-3)混合液中,用过硫酸铵作为氧化剂合成铁磁性导电聚苯胺-钴或铁。所得产物的电导率在10-1~10-2 S cm-1数量级。用振动磁强计测量产物的磁性质,从磁化强度与磁场强度的关系表明:所得产物在常温下具有软铁磁性,而且还可以得到产物的饱和磁化强度和相应的矫顽力。电子顺磁共振波谱表明:产物中具有未成对的电子,产物的电子自旋密度分别为6.01×1019和2.35×1020 spins g-1。紫外光谱和红外光谱表明:钴或铁离子与聚苯胺链上的氮原子发生配位作用,铁磁性导电聚苯胺-钴或铁的骨架结构与反应体系中无金属离子时得到的聚苯胺的骨架结构基本相同;产物的热重图也表明钴离子或铁离子与聚苯胺链存在相互作用。由原子火焰分光光度法和X-衍射测试结果可知:铁磁性导电聚苯胺-钴或铁中仅含微量的金属离子(大约0.5%),这个现象我们可以用Peauson的软硬酸碱理论(HSAB)解释,同时根据XRD图可以得到反应体系中包含钴离子或铁离子时得到的铁磁性导电聚苯胺-钴或铁的结晶度几乎与聚苯胺相同。循环伏安实验结果表明:在含有钴离子或铁离子中合成的聚苯胺具有良好的电化学活性。在外加磁场中利用含有适量过渡金属离子(氯化钴或氯化铁)的苯胺(0.1 mol dm-3)与盐酸(0.5 mol dm-3)混合液,使用过硫酸铵作为氧化剂来合成铁磁性聚苯胺。所得产物的电导率在10-1~10-2 S cm-1数量级。电子顺磁共振波谱表明了在磁场中铁磁性导电聚苯胺-钴或铁的中含有未成对的电子,通过计算得到电子自旋密度相应的也要比无磁场下的要大一些,分别是6.903×1019和7.308×1020 spins g-1,根据磁化强度与磁场强度的关系表明了在磁场中合成出的铁磁性导电聚苯胺-钴或铁具有软铁磁性质,在磁场中所得产物的饱和磁化强度相比无磁场下合成的产物变大了,而相应的矫顽力却减小了。产物的紫外光谱和红外光谱表明:钴或铁离子与聚苯胺链上的氮原子发生配位作用,在磁场中合成的铁磁性导电聚苯胺-钴或铁的骨架结构与反应体系中无金属离子时得到的聚苯胺的骨架结构基本相同;产物的热重图也表明钴离子或铁离子与聚苯胺链存在相互作用。根据原子火焰分光光度法的测试结果和X-衍射图也可知:在磁场中合成的铁磁性导电聚苯胺-钴或铁中仅含微量的金属离子(大约0.5%),这个现象我们可以用Peauson的软硬酸碱理论(HSAB)解释,同时根据XRD图可以得到反应体系中包含钴离子或铁离子时得到的铁磁性导电聚苯胺-钴或铁的结晶度几乎与聚苯胺相同。虽然产物中的金属离子含量很少,但对于相应无磁场下反应合成的铁磁性导电聚苯胺-钴或铁金属含量是有所提高。循环伏安实验结果表明:有磁场下合成的铁磁性导电聚苯胺-钴或铁要比无磁场下合成的铁磁性导电聚苯胺-钴或铁具有更好的电化学活性。更多还原

【Abstract】 Ferromagnetic polyaniline is synthesized in a solution containing 0.1 mol dm-3 aniline, 0.5 mol dm-3 HCl and an adequate content of metallic ions (CoCl2 or FeCl3) at room temperature, using peroxydisulphate as an oxidant (Polyaniline doped with CoCl2 abbreviated as PANI-Co and polyaniline doped with FeCl3 abbreviated as PANI-Fe). Magnetic Properties of PANI-Co and PANI-Fe were measured by Vibrating Sample Magnetometer (VSM), the magnetization (M) versus the applied magnetic field (H) curves showed that PANI-Co and PANI-Fe were soft ferromagnetic properties at room temperature. The saturation magnetization (Ms) of PANI-Co and PANI-Fe were 4.02 emu g-1 (electromagnetic unit per gram) and 5.7 emu g-1, respectively. The conductivities of PANI-Co and PANI-Fe were in the magnitude order of 10-1~10-2 S cm-1. The results of electron paramagnetic resonance (EPR) spectra indicated that the spin density of PANI-Co was 6.01×1019 spins g-1; and the spin density of PANI-Fe was 2.35×1020 spins g-1. The UV-vis and FTIR spectra showed that there was the strong coordination between Co2+ or Fe3+ and N atoms in the PANI chains, but the backbone chains of PANI-Co and PANI-Fe were hardly changed compared with that of PANI, which is confirmed by TGA of PANI-Co and PANI-Fe. According to the results of FAAS, the Co (Fe) content in PANI-Co (PANI-Fe) was about 0.5%, which may be explained by Peauson’s theory of Hard and Soft acids and bases (HSAB). According to XRD the crystallinities of PANI-Co and PANI-Fe were almost the same as the crystallinity of PANI. The results of the cyclic voltammograms indicated that the ferromagnetic PANI-Co and PANI-Fe films were of excellent electrochemical activity.PANI-Co and PANI-Fe were synthesized using peroxydisulphate as an oxidant in a solution containing 0.1 mol dm-3 aniline, 0.5 mol dm-3 HCl and an adequate content of metallic ions (CoCl2 or FeCl3) in the applied magnetic field. The conductivities of the resulting products were in the magnitude order of 10-1~10-2 S cm-1. The EPR spectra displayed that there were unpaired electrons in PANI-Co and PANI-Fe synthesized in the applied magnetic field, the spin density of which were improved (6.903×1019 spins g-1 and 7.308×1020 spins g-1) compared with PANI-Co and PANI-Fe synthesized without magnetic field; The curve of magnetization (M) versus the applied magnetic field (H) showed that PANI-Co and PANI-Fe synthesized under magnetic field had soft ferromagnetic property at room temperature. The saturation magnetization (Ms) of PANI-Co and PANI-Fe synthesized under magnetic field were 6.6 emu g-1 and 6.9 emu g-1 respectively, the saturation magnetization of which increased compared with those of PANI-Co and PANI-Fe in the absence of the applied magnetic field. The UV-vis and FTIR spectra implied that there was the strong coordination between Co2+ or Fe3+ and N atoms in the PANI chains, but the structure of backbone chains of PANI-Co and PANI-Fe with magnetic field hardly changed compared with that of PANI. According to the results of FAAS, the Co (Fe) content in PANI-Co (PANI-Fe) was about 0.5%, which may be explained by Peauson’s theory of Hard and Soft acids and bases (HSAB). According to XRD the crystallinities of PANI-Co and PANI-Fe in the applied magnetic field were almost the same as the crystallinity of PANI. The metal contents (Co and Fe) of the resulting products were a litter higher than those of PANI-Co and PANI-Fe without magnetic field. The results of the cyclic voltammograms indicated that the ferromagnetic PANI-Co and PANI-Fe films with magnetic field were of more excellent electrochemical activity than those without magnetic field.更多还原