Dual Thermo-Responsive and Strain-Responsive Ionogels for Smart Windows and Temperature/Motion Monitoring

Abstract

In this work, a stretchable, dual thermo-responsive and strain-responsive ionogel has been synthesized by one-step photopolymerization. The obtained ionogel shows an ultrahigh stretchability (∼3000%), a high ionic conductivity (up to 3.1 mS/cm), and a good temperature tolerance (−40 to 300 °C). Importantly, these ionogels show an upper critical solution temperature-type phase transition with a wide tunable phase-transition temperature (17.5−42.5 °C) and reversible color/transparency switching. In particular, the as-prepared ionogel-based flexible/wearable temperature monitors and smart windows show an excellent designability and programmability, temperature modulation ability, and thermal responsiveness. Moreover, the ionogels-based strain sensors have temperature-and straindual responsibility and a broad strain-sensing range (1−700%), which can effectively monitor various motions. This strategy of fabricating dual thermo-and strain-responsive ionogels by using a one-step method and only one polymer holds great promise for the next generation of multifunctional stimuli-responsive materials.

Highly Tough, Stretchable, and Recyclable Ionogels with Crosslink-Enhanced Emission Characteristics for Anti-Counterfeiting and Motion Detection

“…Compared with the pre-reported representative ionogels in recent years (Table S2), the as-prepared ionogel has outstanding stretchability, self-healability, and recyclability, making it suitable for fabricating high-performance wearable strain sensors for human motion monitoring. ,,,− Importantly, the LED will turn dark when the ionogel sample is stretched and can brighten with decreasing the strain, indicating good ionic conductivity–strain responsibility of the sensor (Figure a–c). The resistance increases with increasing strain, which causes the geometrical variation of the sample and the decrease of the charge carrier density under tensile mode.…”

“…As shown in Figure d, the ionogel sensor has good sensitivity, and the gauge factor of the strain sensor can reach 3.22 within a wide strain range of 1–700%, which is much higher compared to some reported ionogel-based strain sensors (Table S3). ,− The ionogel-based sensor shows the outstanding electromechanical performance and displays rapid response and recovery times of 98 and 106 ms, respectively (Figure e). Furthermore, the sensor shows rapid electrical response and stable electrical signals during the cutting and healing cycles (Figure f and insets).…”

Elastomeric polymers for conductive layers of flexible sensors: Materials, fabrication, performance, and applications

“…Polymer chains in ionogels can form hydrogen bonds and electrostatic interaction with ILs, giving them unique characteristics such as high ionic conductivity, high thermal and chemical stabilities, a wide electrochemical stability window, stretchability, and self-healing ability. [247,248] The formation of this hydrogen bonding network can provide good compatibility between the polymer matrix and the ILs, reducing the risk of leakage of the IL under large deformation. [249,250] Compared with hydrogels, owing to the negligible vapor pressure of ILs, ionogel-based flexible sensors can work stably in an open atmosphere and even in a vacuum for a prolonged period without performance decrements.…”

Biomimetic Chromotropic Photonic‐Ionic Skin with Robust Resilience, Adhesion, and Stability

“…Sensitivity is a considerable indicator to evaluate sensing performance and is usually quantified by Gauge Factor (GF), which is calculated to be ≈2.31 in the strain range of 0%-80% (Figure 5j), suggesting a better performance compared with recently reported ionogel-based I-skins (Figure S12, Supporting Information). [14][15][16]26,38,42,[44][45][46][47][48][49] This high sensitivity can be attributed to the high content of [EMIM][DCA] and the compatibility between polymer network and IL, which results in excellent electrical conductivity and mechanical properties. The PI-skin with a fast response time (≈270 ms) and recovery time (≈250 ms) can detect strain at different frequencies and output electrical signals independent of frequency (Figure 4c,d), which further proves the reliability and practicability.…”