Ultra-Flexible microwave absorber of PEDOT:PSS/Melamine composite film with wide tunable frequency controlled by Self-Strain sensing

Abstract

The exploration of smart microwave (MW) absorption materials with excellent mechanical properties and wide frequency tuning ability is challenging work. Herein, an ultra-flexible MW absorber with wide frequency modulation by itself strain sensing has been successfully constructed, which is realized by introducing doped conductive poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PEDOT:PSS) with dimethyl sulfoxide (DMSO) into three-dimensional melamine foam (MF) network. The formed MF/P-D20 composite itself is a piezoresistive sensor with a high sensitivity. Most importantly, it is found that the absorption frequency band of the MF/P-D20 composite film can be controllably and reversibly modulated in a wide frequency range from S to Ku bands by changing the compression strain monitored by the value of ΔR/R0. Furthermore, theoretical simulations and experimental findings confirm that the variations of pore shape and size after compression serve as a crucial factor responsible for shifting the enhanced electron flux density and MW loss to higher frequency, which consequently induces the shift of impedance matching and sequent MW absorption to higher frequency. The MW absorber also shows excellent properties of mechanical robustness, thermal insulation, electro-thermal conversion and retardant. This study provides insights into the smart and reversible control of MW absorption properties and paves the way for tuning MW absorption frequency in wide frequency.