Electrically conductive fibers fabrication and characterization via in-situ polymerization of aniline for the protection against EMI and thermal imaging signals

Abstract

Polyester fibers (PEF) were successfully coated with Polyaniline (PANI) via in situ polymerization to make electrically conductive fibers (ECF). X-ray diffraction (XRD) analysis confirms the synthesis and scanning electron microscopy (SEM) confirms the coating of PANI on the surface of PEF. Both coated and uncoated fibers were tested for their DC conductivity, and the results showed a clear difference between the two. From a highly insulating state, it transitions to about 0.1 S/cm. Both the tensile strength and modulus seemed to rise, going from 0.5 MPa to 2.5 MPa and from 0.04 MPa to 0.4 MPa, respectively. Blocking electromagnetic (EM) waves primarily requires a material with good electrical conductivity. The fabric proved effective in blocking about 99.9% of the ultraviolet (UV) and near-infrared rays. Fabrics that effectively block electromagnetic waves are able to conceal the high-temperature human body from a thermal imaging camera, which detects heat signatures by observing the infrared (IR) radiation generated by objects. We also measured the dielectric characteristics using impedance analysis and found that the values for the dielectric constant, dielectric loss, and AC conductivity dramatically increased from the frequency range of 100 Hz to 5 MHz. Further, electromagnetic interference (EMI) and shielding efficiency were determined with the aid of the dielectric constant and dielectric loss (SE). The overall SE in the same 100 Hz to 5 MHz range was similarly more than 80 dB. Improved EMI shielding was feasible due to the non-woven fabric's strong electrical conductivity, homogenous PANI coating on the surface, and great compactness. These findings are enough to predict that these fibers will provide good EMI shielding and thermal imaging when used in any application.