Constructing Uniform Core–Shell PPy@PANI Composites with Tunable Shell Thickness toward Enhancement in Microwave Absorption

作者：Chunhua Tian, Yunchen Du, Ping Xu, Rong Qiang, Ying Wang, Ding Ding, Jianlei Xue, Jun Ma, Hongtao Zhao, Xijiang Han · 发表于：ACS Applied Materials & Interfaces · 年份：2015 · DOI：10.1021/acsami.5b05259 · 被引用次数：514 · 研究领域：Electromagnetic wave absorption materials、Advanced Antenna and Metasurface Technologies、Metamaterials and Metasurfaces Applications

Highly uniform core-shell composites, polypyrrole@polyaniline (PPy@PANI), have been successfully constructed by directing the polymerization of aniline on the surface of PPy microspheres. The thickness of PANI shells, from 30 to 120 nm, can be well controlled by modulating the weight ratio of aniline and PPy microspheres. PPy microspheres with abundant carbonyl groups have very strong affinity to the conjugated chains of PANI, which is responsible for the spontaneous formation of uniform core-shell microstructures. However, the strong affinity between PPy microspheres and PANI shells does not promote the diffusion or reassembly of two kinds of conjugated chains. Coating PPy microspheres with PANI shells increases the complex permittivity and creates the mechanism of interfacial polarization, where the latter plays an important role in increasing the dielectric loss of PPy@PANI composites. With a proper thickness of PANI shells, the moderate dielectric loss will produce well matched characteristic impedance, so that the microwave absorption properties of these composites can be greatly enhanced. Although PPy@PANI composites herein consume the incident electromagnetic wave by absolute dielectric loss, their performances are still superior or comparable to most PANI-based composites ever reported, indicating that they can be taken as a new kind of promising lightweight microwave absorbers. More importantly, microwave absorption of PPy@PANI composites can be simply modulated not ...