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 Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), 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.