A biomimetic laminated strategy enabled strain-interference free and durable flexible thermistor electronics

Abstract

The development of flexible thermistor epidermal electronics (FTEE) to satisfy high temperature resolution without strain induced signal distortion is of great significance but still challenging. Inspired by the nacre microstructure capable of restraining the stress concentration, we exemplify a versatile MXene-based thermistor elastomer sensor (TES) platform that significantly alleviates the strain interference by the biomimetic laminated strategy combining with the in-plane stress dissipation and nacre-mimetic hierarchical architecture, delivering competitive advantages of superior thermosensitivity (−1.32% °C−1), outstanding temperature resolution (~0.3 °C), and unparalleled mechanical durability (20000 folding fatigue cycles), together with considerable improvement in strain-tolerant thermosensation over commercial thermocouple in exercise scenario. By a combination of theoretical model simulation, microstructure observation, and superposed signal detection, the authors further reveal the underlying temperature and strain signal decoupling mechanism that substantiate the generality and customizability of the nacre-mimetic strategy, possessing insightful significance of fabricating FTEE for static and dynamic temperature detection.

Nacre-inspired layered composite gels with broad tunable mechanical strength and structural color for stress visualization

“…3b), proving that the gel has a macroscopically anisotropic structure. 21,31 Meanwhile, it can be seen from the surface and cross-sectional SEM images that the nanoplates are indeed stacked parallel to the gel surface (Fig. 3c and d), further demonstrating that the nanoplates are directionally aligned to form an anisotropic structure under shear-induced action, similar to nacre's BM architecture.…”

“…Inspired by such a structure, researchers used inorganic 2D nanomaterials and organic polymer to fabricate nacre-like structural nanocomposites with light-weight and high strength features. [21][22][23] We can also utilize such structures in colored gels with better mechanical properties. In fact, some particular monolayer nanosheets can self-assemble into liquid crystals (LCs) with swollen lamellar structures balanced by entropic interactions and electrostatic repulsion.…”

A Robust and Adhesive Hydrogel Enables Interfacial Coupling for Continuous Temperature Monitoring

“…Thermistor hydrogels, sharing structural and mechanical similarities with human skin and can be engineered with tunable thermosensation properties, which are considered as promising interfacial bridging media between biological systems and AES, stand out in addressing the above conundrum. [ 13–16 ] To date, extensive efforts have focused on exploring hydrogel‐based thermistor epidermal sensors (HTES) with negative temperature coefficient, which mainly rely on incorporating thermosensitive moieties with flexible elastomeric substrate or encapsulating thermoelectric network configuration with dielectric layer, including reduced graphene oxide (rGO), [ 17 ] silver nanowires (AgNWs), [ 18 ] MXene nanosheets, [ 19 ] poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), [ 20 ] and carbon nanotubes (CNTs), [ 21 ] combining complementary advantages of thermosensitivity and skin‐like conformability. In a noteworthy work, Wang et al.…”

MXene‐based dual‐network conductive organic hydrogel for wearable sensor to monitor human motions

“…Conductive hydrogels have received more and more attention, especially their dual network structure has also attracted the attention of many scholars. [1][2][3] At the same time, conductive hydrogels can be used to create flexible wearable strain sensors because of their superior electronic properties, excellent mechanical capabilities, and exceptional biological properties. [4][5][6] However, conductive hydrogels using pure water as the medium freeze at below-freezing temperatures, resulting in loss of their elasticity and conductivity and limiting their practical applications, such as flexible strain sensors.…”

“…Conductive hydrogels have received more and more attention, especially their dual network structure has also attracted the attention of many scholars 1–3 . At the same time, conductive hydrogels can be used to create flexible wearable strain sensors because of their superior electronic properties, excellent mechanical capabilities, and exceptional biological properties 4–6 .…”