Hyper-crosslinked Conjugated Microporous Polymers with Increased Micropores Promotes Confining Polymerization for Electromagnetic Absorption Application

Conjugated microporous polymers have excellent skeleton structures but poor electrical conductivity limits their applications in microwave absorption. To solve this problem, a strategy of molecular expansion and confining polymerization is proposed in this work to synthesize conductive hyper-crosslinked conjugated microporous polymer. The topology of the conjugated microporous polymer is changed into a three-dimensional skeleton structure with high specific surface area by using molecular expansion technique, and the controlled growth of polypyrrole in the channel constructs a unique network structure. The balance of excellent composite backbone structure, proper conductivity, attenuation capability and impedance matching enable the material to exhibit electromagnetic wave absorption performance. As a result, with low filler loading of 10 wt%, a strongest reflection loss of −52.68 dB and a maximum effective bandwidth of 5.76 GHz. Additionally, CST simulations of the radar scattering cross section have been carried out to verify the excellent material properties. This study provides new concepts for new conductive polymers and broadens the application of hyper-crosslinked conjugated microporous polymer in the field of electromagnetic wave absorption.