A multi-functional wearable sensor based on carbon nanomaterials reinforced TPU fiber with high sensitivity

Wearable flexible strain sensors have attracted increasing research interest due to their potential applications in motion detection, healthcare, human-computer interaction, and artificial intelligence. In this work, a novel kind of conductive PDMS/(CB+CNTs)/TPU composite was prepared and applied for assembling a flexible strain sensor, i.e., thermoplastic polyurethane (TPU) as a polymer matrix, carbon black (CB) and carbon nanotubes (CNTs) as hybrid conductive nanofillers, and then modified by polydimethylsiloxane (PDMS) for achieving super-hydrophobicity. Experimental results reveal that the sensor exhibits the advantages: 1) Excellent mechanical properties, i.e., the tensile strength of the composite increased from 5.88 MPa to 8.88 MPa; 2) Excellent sensing performances, i.e., the highest sensitivity up to 49,863.5, and high repeatability and durability during a cyclic tension-release test (50% strain); 3) Multi-functions include good electrical conductivity, super-hydrophobicity with a static water contact angle as high as 152°, and favorable flexibility; 4) It possessed a high cost-performance ratio due to the simple preparation process, i.e., electrospinning, ultrasonic adsorption treatment, and PDMS modification, and cheap raw materials, such as PDMS, CB, and TPU when compared with similar sensors. The sensor is applied to monitor and detect the full range of human body movements, such as joint movement, breathing, coughing, and speaking, which shows broad application prospects in wearable electronic products.