HCl guided morphology and conductivity of chiral PPy nanostructures toward efficient electromagnetic wave absorption

Abstract

To solve the severe electromagnetic (EM) radiation from the widespread application of electronic equipment, we developed a simple template-guided oxypolymerization strategy to synthesize polypyrrole (PPy) planar helixes as an efficient EM wave (EMW) absorber, and systematically investigated the morphology-dependent chirality, conductivity, and microwave absorption properties. As HCl concentration [HCl] varied from 0 to 2.0 M, the morphology evolved from planar helix to 3D cross-linking network structures, the conductivity increased from 0.0019 to 0.0302 S/cm, and the EM parameters peaked at [HCl]=0.5 M. Compared to other absorbers, the PPy planar helix formed at [HCl]=0 M possessed wider absorption band (5.84 GHz), smaller matching thickness (1.6 mm), lower loading (25 wt.%), and intenser absorption (−48.17 dB). The reason lies in the strong attenuation capability, multiple resonances, multiple scattering, and good impedance matching generated by chiral PPy planar helixes with a distinctive helical configuration, doped heteroatoms (O,S), and a local conductive network. Our results suggest that PPy planar helixes offer great promise for fields such as chiral sensors, electronics, optics, chiral catalysis, and EMW absorption and shielding due to their distinctive morphology, tunable conductivity, and outstanding EMW absorption properties (EMWAPs).

Addressing Triboelectric Nanogenerator Impedance for Efficient CO2 Utilization

“…It is important to note that as the HCl content increased, the peaks shifted toward lower wavenumbers (see Figure S3, Supporting Information). This shift is related to more delocalized carriers in the PPy film, [ 34 ] which facilitates electronic conductivity, as demonstrated in Figure S4 (Supporting Information).…”

“…The PPy chains became protonated as dopant cations (H + ) entered, acquiring positive charges that were counterbalanced by the presence of Cl − ions. [34] The BT-PVP composite film was The synthesized materials underwent Fourier-Transform Infrared Spectroscopy (FTIR) and the results are also presented in Figure 1c. For BT-PVP, the C─N bending vibration at 1290 cm −1 originates from the pyrrolidone structure of PVP, and the vibrational peak assigned at 1425 cm −1 is attributed to the COO − group bending vibrations of BT powder.…”

“…The PPy chains became protonated as dopant cations (H + ) entered, acquiring positive charges that were counterbalanced by the presence of Cl − ions. [ 34 ] The BT–PVP composite film was created through physical blending, which involved thoroughly mixing barium titanate (BT) with polyvinylpyrrolidone (PVP) dissolved in ethanol.…”

Fabrication of One-Dimensional Polypyrrole Nanochains for a High-Efficiency Electromagnetic Wave Absorber with a Low Filler Loading

“…Except for PPy NPs, one-dimensional (1D) hollow PPy nanorods and PPy nanofibers were also exploited as highly efficient EWAMs with lower filler contents due to their structural advantage. Moreover, Yang et al synthesized PPy planar helixes with three-dimensional (3D) cross-linking network structures and investigated the effect of the doping hydrochloric acid (HCl) concentration on the wave-absorption property. It was concluded that the PPy planar helix formed at [HCl] = 0 M possessed an optimal wave-absorption performance.…”