Conductive Cellulose-Based Fibers for Electromagnetic Wave Absorption, Pressure Sensing, and Antibacterial Activity

The growing issue of electromagnetic pollution has generated a significant demand for multifunctional wearable textiles with electromagnetic wave (EMW) absorption. In this study, a multifunctional conductive cellulose-based composite fiber has been fabricated by wet spinning. A continuous conductive layer composed of polypyrrole (PPy) and carboxylated multiwalled carbon nanotubes (c-MWCNTs) was uniformly deposited on the surface of regenerated cellulose fibers (RCF) through in situ polymerization. The electrical conductivity of the resultant fibers could be improved to 127.12 S/m, benefiting from the addition of c-MWCNTs. Owing to multiple interactions between PPy and c-MWCNTs, including physical adsorption, hydrogen bonding, and π-π conjugation, the as-obtained composite fibers showed excellent electrical conductivity stability in abrasion resistance and washing durability tests. Due to the improvement in impedance matching by a conductive network and multiple loss mechanisms, the composite fibers exhibited excellent EMW absorbing properties with an excellent minimum reflection loss (RL_min) of -43.46 dB and a broad effective absorption bandwidth (EAB) of 7.95 GHz. Additionally, the composite fibers also displayed remarkable antibacterial activity against <i>Staphylococcus aureus</i> (<i>S. aureus</i>) and <i>Escherichia coli</i> (<i>E. coli</i>), as well as outstanding sensing performances for monitoring pressure with a high sensitivity of 1.10 kPa ^-1 over a range of 0-10 kPa.