Commonly Neglected Ester Groups Enhanced Microwave Absorption

Abstract

Oxygen‐containing functional groups have high potential to excite polarization loss. The nature and mechanism of the polarization loss brought on by oxygen‐containing functional groups, however, remain unclear. In this study, metal‐organic framework precursors are in situ pyrolyzed to produce ultrathin carbon nanosheets (UCS) that are abundant in oxygen functional groups. By altering the pyrolysis temperature, the type and concentration of functional groups are altered to produce good microwave absorption capabilities. It is demonstrated that the main processes of electromagnetic loss are polarization caused by “field effects and induced effects” brought on by strongly polar ester functional groups. Moreover, links between various oxygen functional groups and structural flaws are established, and their respective contributions to polarization are sharply separated. The sample with the highest ester group content ultimately achieves an effective absorption bandwidth of 6.47 GHz at a pyrolysis temperature of 800°C. This research fills a theoretical hole in the frequently overlooked polarization mechanism in the microwave band by defining the key polarization parameters in chaotic multiple dipole systems and, in particular, redefining the significance of ester groups.

A Novel Low-Density-Biomass-Carbon Composite Coated with Carpet-like and Dandelion-Shaped Rare-Earth-Doped Cobalt Ferrite for Enhanced Microwave Absorption

“…These residual elements in BC had high polarity and tended to form more polar functional groups [ 26 , 27 , 28 ]. The presence of polar functional groups has been favorably documented as enhancing the absorption proficiency of the material [ 29 ]. Consequently, BC may have good absorption properties.…”

MoS2-Based Nanocomposites for Microwave Absorption: A Review

“…For example, thermal conductivity absorbing material is a new type of multifunctional electromagnetic protection material; with the rapid development of electronic equipment, the performance requirements of thermal conductivity absorbing indicators are getting higher and higher. 142 Developing new composite materials with both high thermal conductivity and electromagnetic wave absorption functions will be a major research focus in the future. Flexible and compressible microwave absorbing materials have great potential applications in wearable electronics to protect human health.…”

“…From the micro and macro point of view, the absorption mechanisms inside and outside the material are studied and their contribution to the performance is analyzed. MoS 2 -based microwave absorbing materials need to be developed in the direction of multifunction. For example, thermal conductivity absorbing material is a new type of multifunctional electromagnetic protection material; with the rapid development of electronic equipment, the performance requirements of thermal conductivity absorbing indicators are getting higher and higher . Developing new composite materials with both high thermal conductivity and electromagnetic wave absorption functions will be a major research focus in the future.…”