Ferrite-grafted polyaniline nanofibers as electromagnetic shielding materials
Ferrite-grafted polyaniline nanofibers as electromagnetic shielding materials
复制标题
DOI：
10.1039/c3tc00757j
复制
发表时间：
2013-03
影响因子：
6.4
通讯作者：
Wenjie Wang;S. Gumfekar;Q. Jiao;Boxin Zhao
中科院分区：
文献类型：
--
作者：
Wenjie Wang;S. Gumfekar;Q. Jiao;Boxin Zhao
采用原位乳液聚合法成功制备了具有高介电吸波性能和低频电磁屏蔽性能的Mn0.5Zn0.5Fe2O4/聚苯胺纳米复合材料。采用盐酸掺杂聚苯胺（PANI），以改善其电学性能和与铁氧体纳米粒子的相互作用。静电力、顺磁力和氢键作用使铁氧体纳米粒子在聚苯胺表面牢固地键合或组装，提高了聚苯胺纳米结构的热稳定性。聚苯胺纳米纤维的平均直径为100 nm，长度为500 nm，由一束较小的单个单元组成，而铁氧体纳米颗粒为球形，平均直径为30 nm。研究结果表明，铁氧体粒子克服了聚苯胺的团聚问题，均匀地分散在聚苯胺表面。铁氧体接枝聚苯胺纳米结构被证明是一种很有前途的功能材料，用于吸收电磁微波，因为大量的偶极极化的聚合物主链和在铁氧体纳米粒子和聚苯胺纳米纤维的界面。铁氧体接枝聚苯胺纳米复合材料的复介电常数和屏蔽效能均随着聚苯胺重量百分比的增加而增加。复介电常数的真实的部分和虚部也有很好的匹配，从而在测量频率（30 MHz至1 GHz）下产生几乎相等的介电损耗角正切。这种上级性质允许纳米复合材料在扩展的吸收带内起作用。
A functional structure of Mn0.5Zn0.5Fe2O4-on-polyaniline nanocomposites with high dielectric absorbing properties and electromagnetic shielding effectiveness at low frequencies was successfully fabricated through a facile in situ emulsion polymerization. Polyaniline (PANI) was doped with hydrochloric acid to improve its electrical properties and interactions with ferrite nanoparticles. The electrostatic force, paramagnetic force and hydrogen bonding strongly bonded or assembled ferrite nanoparticles on the polyaniline surface and improved the thermal stability of the polyaniline nanostructure. Polyaniline nanofibers were found to have an average diameter of 100 nm and length of 500 nm, consisting of a bundle of smaller individual units, whereas ferrite nanoparticles were of spherical shape with an average diameter 30 nm. The research findings show that ferrite particles overcome the common problem of aggregation and evenly dispersed on the surface of polyaniline. The ferrite-grafted polyaniline nanostructures were demonstrated as a promising functional material for the absorbing of electromagnetic microwaves because of a large amount of dipole polarizations in the polymer backbone and at the interfaces of the ferrite nanoparticles and polyaniline nanofibers. Both the complex permittivity and shielding effectiveness of the ferrite-grafted polyaniline nanocomposites increased with the increasing weight percentage of PANI. There is also a good match of real and imaginary parts of the complex permittivity, giving rise to almost an equal dielectric loss angle tangent in the measured frequency (30 MHz to 1 GHz). This superior property allows the nanocomposites to function within an extended absorbing band.