posted on 2020-04-01, 11:43authored byChang Xu, Fan Wu, Aming Xie, Liqun Duan, Zhiqian Yang, Yilu Xia, Mengxiao Sun, Ziming Xiong
Developing
materials with large-scale, ultralight, tunable dielectric
properties to meet the applications in electromagnetic (EM) pollution
management is still a long-standing issue. In this study, a kind of
polypyrrole (PPy) aerogel is fabricated on a large scale through the
self-assembly of hollow PPy nanofibers. Benefitting from the first
reported “seeding” route method, the diameters and dielectric
properties of the PPy nanofibers can be controlled by modulating the
proportion of hollow PPy nanofiber seeds and pyrrole (Py). By optimizing
the component proportion, the hollow PPy nanofiber aerogel can be
applied in both microwave absorption and electromagnetic interference
(EMI) shielding. It was found that a minimum reflection loss value
of −58.73 dB and a wide effective absorption bandwidth of 7.28
GHz were obtained for the seeds and Py proportion of 1:0.5. Moreover,
by modulating the proportion to 1:2, the EMI shielding effectiveness
of a composite loaded with 20 wt % of hollow PPy nanofiber aerogels
can reach 68.92 dB under the thickness of 3.0 mm. A well-defined conductive
network of PPy nanofibers and various interface polarizations and
multireflections between different PPy nanofibers and hollow pipes
may be the main reasons for the excellent performance in EM applications.
This work provides a new strategy of hollow PPy nanofiber aerogels
for EM protection.