Fabrication, evaluation, and mechanism of TPU nanocomposites containing MWCNTs–Fe2O3 hybrid conductive nanofillers for selective VOC sensing applications

Abstract

AbstractVolatile organic compounds (VOCs) are highly harmful substances that can bring serious harm to the environment and human health. In this work, thermoplastic polyurethane (TPU) conductive nanocomposite sensors for selective gas sensing of VOCs were designed and fabricated using electrospun TPU fibers as templates and MWCNTs–Fe2O3 as conductive hybrid nanofillers through a homogeneous liquid impregnation method. The microstructure of TPU matrix fibers and the TPU nanocomposites, and their gas‐sensitive response performance to various VOCs, were investigated. The formation of MWCNTs–Fe2O3 nanofillers was confirmed by Fourier transform infrared spectroscopy, X‐ray diffraction, and Raman analysis. Field emission scanning electron microscope showed that MWCNTs–Fe2O3 nanofillers were uniformly coated on the surface of TPU, forming effective and complete conductive networks. The average volume resistivity of TPU nanocomposites (containing 4.76 wt% MWCNTs–Fe2O3) was reduced from 1.5 × 1012 Ω·mm in pure TPU matrix fiber to 2.93 × 105 Ω·mm. Gas‐sensitive performance tests with 500 ppm of ether, ammonia, formaldehyde, ethanol, xylene, toluene, benzene vapor, and acetone showed that the response value of TPU/MWCNTs–Fe2O3 nanocomposites to ether was 85.7%, and the resistance ratio of desorption to the initial one was 1.01, which was almost a complete recovery. In addition, the gas response values of TPU nanoconductive composites under different humidity environments show better stability.Highlights Novel TPU composites contain MWCNTs–Fe2O3 conductive nanofillers were proposed. Synthesized TPU nanocomposite fibers by electrospinning and liquid dip methods. TPU nanocomposite sensors combine fast response, selectivity, and repeatability. TPU nanocomposites exhibited high gas‐sensitive response selectivity to ether.