Multifunctional Flexible Sensor Based on PU‐TA@MXene Janus Architecture for Selective Direction Recognition

Abstract

Multifunctional selectivity and mechanical properties are always a focus of attention in the field of flexible sensors. In particular, the construction of biomimetic architecture for sensing materials can endow the fabricated sensors with intrinsic response features and extra‐derived functions. Here, inspired by the asymmetric structural features of human skin, a novel tannic acid (TA)‐modified MXene‐polyurethane film with a bionic Janus architecture is proposed, which is prepared by gravity‐driven self‐assembly for the gradient dispersion of 2D TA@MXene nanosheets into a PU network. This obtained film reveals strong mechanical properties of a superior elongation at a break of 2056.67% and an ultimate tensile strength of 50.78 MPa with self‐healing performance. Moreover, the Janus architecture can lead to a selective multifunctional response of flexible sensors to directional bending, pressure, and stretching. Combined with a machine learning module, the sensor is endowed with high recognition rates for force detection (96.1%). Meanwhile, direction identification in rescue operations and human movement monitoring can be realized by this sensor. This work offers essential research value and practical significance for the material structures, mechanical properties, and application platforms of flexible sensors.

Materials-Driven Soft Wearable Bioelectronics for Connected Healthcare

“…Inspired by asymmetric structural features of human skin, a bionic Janus structure composed of a tannic acid (TA)-modified MXene-PU film was proposed showing a selective multifunctional response to directional bending, pressure, and stretching. 237 The Janus architecture was obtained by gravity-driven self-assembly for the gradient dispersion of 2D TA-MXene nanosheets into the PU network. A film with over 2056% breaking point of elongation and an ultimate tensile strength of 50.78 MPa accompanied with selfhealing performance was formed.…”

“…Notably, in vitro tests proved the considerable biocompatibility and biodegradability of the MXene silk nanomembrane. Inspired by asymmetric structural features of human skin, a bionic Janus structure composed of a tannic acid (TA)-modified MXene-PU film was proposed showing a selective multifunctional response to directional bending, pressure, and stretching . The Janus architecture was obtained by gravity-driven self-assembly for the gradient dispersion of 2D TA-MXene nanosheets into the PU network.…”

Topological MXene Network Enabled Mixed Ion–Electron Conductive Hydrogel Bioelectronics

“…Figure 1c shows the content of MXene topology in the hydrogel. According to recently reported research, 20 we performed a small-angle X-ray scattering to verify the gradient MXene structure. As shown in Figure S2a, with an increase in incidence angle, the intensity of the (002) peak is enhanced, and the scattered light spot becomes brighter (Figure S2b−f).…”

Normal-Direction Graded Hemispheres for Ionic Flexible Sensors with a Record-High Linearity in a Wide Working Range

“…Alongside the development in wearable sensors, biochemical sensors, flexible multimodal sensors, , and pressure sensors, the manufacturing technology and fabrication process level of sensors and circuits on flexible films have witnessed significant improvement. − Among them, pressure sensors are particularly relevant to this advancement. − Capacitive flexible pressure sensors, commonly used in this field, possess advantages such as simple device structure, stable signal, and low energy consumption. , As a core parameter, the sensitivity has shown significant improvement in recent research. The ionic flexible pressure sensor (IFS) introduces the electronic double layer effect (EDL) at the dielectric (such as ionic nanofibrous or gel membranes) or electrode interface, − which greatly enhances sensitivity through the unique ultrahigh specific capacitance of the nanoscale ion–electron interface. − Innovative design of microstructures on the ion–electron interface is one of the most effective ways to enhance sensor performance, , offering a broad range of design options, including regularly raised peaks, , microcolumn arrays, dome-like structures, , and surface patterns formed by randomly distributed microstructures (molded using sandpaper or natural templates) , due to their higher compressibility compared to just one planar dielectric layers.…”