Flexible Strain Sensor Enabled by Carbon Nanotubes‐Decorated Electrospun TPU Membrane for Human Motion Monitoring

Abstract

Bin (2023) Flexible strain sensor enabled by carbon nanotubesdecorated electrospun TPU membrane for human motion monitoring. Advanced Materials Interfaces. p. 2202292.

Polydopamine/Carbon Black/Carbon Nanofiber/Thermoplastic Polyurethane Composite Nanofiber Strain Sensor with Ultrahigh Loading Rate for Human Activity Monitoring

“…To determine the preparation of CNF, the anchored loading of carbon nanomaterials, and the surface deposition of PDA, the samples of PAN, CNF, and each step were tested for XRD characterization in the range of 10 to 90° (2θ) (Figure a). Based on the short-range ordering in the molecular chains of TPU and the disordered structure of the amorphous phase, a broad characteristic diffraction peak at 2θ = 21.2° exists, while the broad peaks at around 24.4 and 44.1° for CNF represent the (002) and (100) crystal planes, respectively, belonging to graphitic carbon, which demonstrates the formation of the graphitic structure in CNF, and the weak intensity of the (100) peak proves a good degree of degree of graphitization. − After the subsequent attachment of carbon nanomaterials and the PDA coating process, the peaks occur accordingly shifted due to the large amount of coupling between the encapsulation layer, conductive filler and the substrate . For example, during the ultrasonic attachment process, the cavitation bubbles collapse on the surface of the carbon nanomaterials and generate high-frequency oscillating jets, which drive them to bombard TPU nanofibers at high speed to produce interface collisions, at which time the kinetic energy is converted into thermal energy, resulting in transient high temperatures on the surface of the fiber microarea and softening or melting.…”

“…Based on previous studies, increasing the loading sites of the substrate or the loading rate per unit area to improve the anchoring amount of the active filler can increase the density of the conductive network as well as the conductivity in the functional layer, expand the resistance variation interval, and thus improve the sensitivity and response range of the device . The porous structure and nanoscale present in the nonwoven fiber membranes prepared by the electrospinning process enable them to have a specific surface area and surface activity that far exceed those of dense membranes, which can provide more loading sites and attachment efficiency, and thus are often used as a reliable choice for CPC sensor substrates. , By anchoring CNT to thermoplastic polyurethane (TPU) nanofiber membranes, Yu et al prepared a composite fiber sensor that achieved a gauge factor (GF) of 110.0 in the commonly used response range of 0–50%, with the corresponding wet-spun-prepared micron fiber substrate performing at only 10.2. , Significant increases in loading rates can be achieved by improving the dispersion of the active filler or its compatibility with the substrate, inhibiting agglomeration of the active material, and promoting selective adsorption with the substrate. As nonpolar material with inert surface, CB and CNF tend to agglomerate in water with low dispersibility.…”

“…Yu et al utilized surface modification with PDA to obtain adhesive DATPU substrates. The adhesive linkage of PDA amplified the destruction intensity of the conductive layer during strain, allowing it to exhibit a GF of 208.9 (0–50%), which is twice that of the TPU substrate (GF = 110.0) …”

“…13,14 By anchoring CNT to thermoplastic polyurethane (TPU) nanofiber membranes, Yu et al prepared a composite fiber sensor that achieved a gauge factor (GF) of 110.0 in the commonly used response range of 0−50%, with the corresponding wet-spun-prepared micron fiber substrate performing at only 10.2. 15,16 Significant increases in loading rates can be achieved by improving the dispersion of the active filler or its compatibility with the substrate, inhibiting agglomeration of the active material, and promoting selective adsorption with the substrate. As nonpolar material with inert surface, CB and CNF tend to agglomerate in water with low dispersibility.…”

High ionic conductive, freezing-resistant and transparent polyurethane based on a novel metal ionic deep eutectic solvent

“…Among them, one prominent representative is polyurethane. 19,20 However, due to the unique soft and hard segmentation of PU, micro-phase separation will occur inside PU, 21,22 which will degrade the properties of these composite materials, such as transparency 9,10 and electrical conductivity. The degradation of these properties will further affect the performance of electronic devices, including durability and appearance.…”