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Wearable sensors are currently one of the top emerging areas with enormous growth potential. Low‐cost fabrication techniques using simple and scalable printing technologies are making a significant impact on their development. Recent advances in high‐performance gas/vapor sensors based on carbon nanomaterials have shown potential applications ranging from disease diagnostics to environmental monitoring and defences. Herein, a hybrid sensing material of 1D carbon nanotubes (CNTs) and 2D graphene is developed, and a conductive ink is formulated, which is applied for fabricating a nitrogen dioxide (NO2) gas sensor array within a compact design utilizing extrusion printing. To improve NO2‐sensing performance and optimal operating temperature, a reverse‐side layer is designed, which combines MXene and poly(3,4‐ethylenedioxythiophene)‐doped poly(styrene sulfonate) (PEDOT:PSS), and functions as a Joule heater. The printed CNT–graphene‐based sensor with an embedded MXene/PEDOT:PSS heater is capable of detecting trace amounts of NO2 gas (1 ppm) at 65 °C. The sensor is able to distinguish between various gases/volatile organic compounds and target NO2 gas based on their chemical affinities. The printed CNT–graphene sensor array also demonstrates a high‐level of recoverability, satisfied stability, durability, and reproducibility, which render this sensor a suitable candidate for practical applications. [ABSTRACT FROM AUTHOR]

The valorization of onion-like carbon nanoparticles (OCNPs) from pollutant soot collected from diesel engine exhaust could be a promising and sustainable approach to develop percolated conductive networks in a poly(lactic acid) (PLA) matrix, which could be used for the design of conductive polymer nanocomposite (CPC)-based quantum resistive sensors (QRS). The aim of the present study is to incorporate these waste materials in the field of structural health monitoring (SHM) of biocomposites. Here, OCNPs have been used in the formulation of QRS and further integrated into unidirectional flax fibers and PLA composites for SHM trials without altering their mechanical properties. QRS transducers made of 1 wt% OCNPs dispersed into a PLA matrix have been prepared via an in situ spray layer-by-layer (sLbL) process during the fabrication of flax–PLA composites by film stacking under vacuum conditions. Their in situ sensing of strain and damage was evaluated by submitting the flax–PLA unidirectional composite samples to various incremental and simultaneous loading–unloading cycles. Most importantly, the piezo-resistive behavior of the OCNP-based QRS has been found to be reproducible, and it exhibits large-amplitude signals with a gauge factor of 6 ± 2, which is two to three times larger than that of commercial strain sensors. Additionally, these waste-derived OCNPs possess interesting ferromagnetic properties at room temperature. [ABSTRACT FROM AUTHOR]

A correction to the article "Electromagnetic properties of Fe3O4-Functionalized Graphene and Its Composites with a Conducting Polymer," that was published online on June 5, 2013 issue is presented.