title: Constructing Uniform Core-Shell PPy@PANI Composites with Tunable Shell Thickness toward Enhancement in Microwave Absorption.
abstract: 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 only by the thickness of the absorbers, but also the shell thickness to satisfy the applications in different frequency bands.
authors: Department of Chemistry, Harbin Institute of Technology , Harbin 150001, China.
authors: Chunhua
authors: C
authors: Tian
authors: Department of Chemistry, Harbin Institute of Technology , Harbin 150001, China.|State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology , Harbin 150001, China.|HIT-HAS Laboratory of High-Energy Chemistry and Interdisciplinary Science, Harbin Institute of Technology , Harbin 150001, China.
authors: Yunchen
authors: Y
authors: Du
authors: Department of Chemistry, Harbin Institute of Technology , Harbin 150001, China.
authors: Ping
authors: P
authors: Xu
authors: Department of Chemistry, Harbin Institute of Technology , Harbin 150001, China.
authors: Rong
authors: R
authors: Qiang
authors: Department of Chemistry, Harbin Institute of Technology , Harbin 150001, China.
authors: Ying
authors: Y
authors: Wang
authors: Department of Chemistry, Harbin Institute of Technology , Harbin 150001, China.
authors: Ding
authors: D
authors: Ding
authors: Physics Section, Medical Technology Department, Qiqihar Medical University , Qiqihar, Heilongjiang 161006, China.
authors: Jianlei
authors: J
authors: Xue
authors: State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology , Harbin 150001, China.
authors: Jun
authors: J
authors: Ma
authors: HIT-HAS Laboratory of High-Energy Chemistry and Interdisciplinary Science, Harbin Institute of Technology , Harbin 150001, China.|Institute of Technical Physics, Heilongjiang Academy of Sciences , Harbin 150009, China.
authors: Hongtao
authors: H
authors: Zhao
authors: Department of Chemistry, Harbin Institute of Technology , Harbin 150001, China.
authors: Xijiang
authors: X
authors: Han
keywords: core−shell; interfacial polarization; microwave absorption; polypyrrole@polyaniline; shell thickness