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 d B 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.

Hydrogen peroxide mediates high-intensity blue light-induced hypocotyl phototropism of cotton seedlings

Phototropism is a classic adaptive growth response that helps plants to enhance light capture for photosynthesis.It was shown that hydrogen peroxide(H_(2)O_(2))participates in the regulation of blue light-induced hypocotyl phototropism;however,the underlying mechanism is unclear.In this study,we demonstrate that the unilateral high-intensity blue light(HBL)could induce asymmetric distribution of H_(2)O_(2) in cotton hypocotyls.Disruption of the HBL-induced asymmetric distribution of H_(2)O_(2) by applying either H_(2)O_(2) itself evenly on the hypocotyls or H_(2)O_(2) scavengers on the lit side of hypocotyls could efficiently inhibit hypocotyl phototropic growth.Consistently,application of H_(2)O_(2) on the shaded and lit sides of the hypocotyls led to reduced and enhanced hypocotyl phototropism,respectively.Further,we show that H_(2)O_(2) inhibits hypocotyl elongation of cotton seedlings,thus supporting the repressive role of H_(2)O_(2) in HBL-induced hypocotyl phototropism.Moreover,our results show that H_(2)O_(2) interferes with HBL-induced asymmetric distribution of auxin in the cotton hypocotyls.Taken together,our study uncovers that H_(2)O_(2) changes the asymmetric accumulation of auxin and inhibits hypocotyl cell elongation,thus mediating HBL-induced hypocotyl phototropism.