Laser Direct Writing of Flexible Sensor Arrays Based on Carbonized Carboxymethylcellulose and Its Composites for Simultaneous Mechanical and Thermal Stimuli Detection

Abstract

Multifunctional sensing devices with high flexibility, high sensitivity, and scalable fabrication are inevitable components of Internet of Things (IoT) for human−machine interfaces, structural health monitoring, and soft robots. Herein, high-performance flexible sensor arrays using carboxymethylcellulose (CMC) and its composite were developed for mechanical and thermal stimuli detection by laser direct writing. CMC contains abundant carbon precursors for strainsensitive laser-carbonized CMC (LC-CMC), while the incorporation of graphene oxide (GO) into CMC leads to the formation of thermalsensitive laser-carbonized GO/CMC (LC-GO/CMC). The LC-CMC-based strain sensor delivers gauge factors of 487.7 (strain < 8.5%) and 8557 (8.5% < strain < 14%), with long-term stability over 10 000 cycles. With 0.2 wt % GO, the LC-GO/CMC-based device provides a temperature coefficient of resistance of −0.289% °C −1 , higher than the Cr-based commercial sensor. The potential application of the devices in IoT is proved by combining the near-field communication technology with the LC-CMC-based device to monitor the strain suffered by 316L stainless steel during the fatigue test. Moreover, an integrated device based on the strain and temperature sensing arrays accomplishes the simultaneous measurement of temperature and mechanical deformation in real time.

Channel-Crack-Designed Suspended Sensing Membrane as a Fully Flexible Vibration Sensor with High Sensitivity and Dynamic Range

“…The capacity of detecting acceleration vibration could effectively expand the application area of the sensors. The performance comparison of the proposed sensor with a related flexible strain/vibration sensor ,,,,,− is shown in Table S1. Owing to the embedded sensing structure and crack-based widening sensing mechanism, the proposed sensing membrane shows both good sensitivity and stability.…”

Ultra‐Stretchable Monofilament Flexible Sensor with Low Hysteresis and Linearity based on MWCNTs/Ecoflex Composite Materials

“…The field of strain sensors based on CNTs and highly flexible composites has been well developed. [18][19][20] For example, cracking treatment is used to improve sensor performance, and other preparation methods such as 3D printing [21][22][23] and laser direct writing [22,24,25] are used to innovate sensor structure. At the same time, conductive polymer composites based on typical conductive materials have been widely used.…”

Wearable Sensors Based on Solid-Phase Molecular Self-Assembly: Moisture-Strain Dual Responsiveness Facilitated Extremely High and Damage-Resistant Sensitivity

“…To meet these requirements, people have endeavored to design various conductive soft materials. − Soft materials used in wearable sensors are often flexible polymer films resulting from solvent evaporation or hydrogels. − Except for flexible films made with elegantly designed conductive polymers, , few soft materials are intrinsically conductive. For this reason, carbon nanotubes, − graphene, − silver nanowires, − inorganic salts, − and ionic liquids , were often doped to achieve desired conductivity. Inkjet printing, laser manufacturing, and 3D printing of these materials on a soft substrate were also employed to create patterned sensors.…”