Tao Lv,ZeWen Li,ChunYu Lv,XinYu Zhang,Ye Li,Mengying Xie
Flexible sensors with a single tactile sensing function have been extensively studied, however, the development of highly sensitive multifunctional sensors remains a significant challenge in the realm of wearable technology. In this paper, a multifunctional flexible capacitive sensor with integrated proximity, pressure and temperature perception is developed. The dielectric layer of the sensor is obtained by spontaneous polymerization of polyvinyl alcohol and the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide at room temperature. The electrode structure is optimized by leveraging the capacitive fringing field effect, and the designed hole-circle shaped 4 × 4 electrode array achieves optimal proximity sensitivity with a maximal capacitance drop of 0.54 pF to human hand and a detection distance of 30 mm. Besides, the prepared microcone structure sensor exhibits high pressure sensitivity of 4.822 kPa-1(0-5 kPa), rapid response time (<100 ms), a broad detection range (~200 kPa), and excellent stability over 3000 cycles of loading/unloading tests. By exploiting the temperature dependence of the ionic liquid, the sensor also exhibits high temperature sensitivity of 80.6%°C-1(25-80°C). Finally, we verified the successful application of this sensor in dynamic finger trajectory recognition, multi-touch and robotic grasping state detection, paving the way for its use in artificial intelligence, healthcare, and intelligent robotics.
Stretchable ionic hydrogels with superior all-round properties that can detect multimodal sensations with excellent discriminability and robustness against external disturbances are highly required for artificial electronic skinapplications. However, some critical material parameters exhibit intrinsic tradeoffs with each other for most ionic hydrogels. Here, a microphase-separated hydrogel is demonstrated by combining three strategies: (1) using of a low crosslinker/monomer ratio to obtain highly entangled polymer chains as the first network; (2) the introduction of zwitterions into the first network; (3) the synthesis of an ultrasoft polyelectrolyte as the second network. This all-round elastic ionic hydrogel exhibits a low Young's modulus (< 60 kPa), large stretchability (> 900%), high resilience (> 95%), unique strain-stiffening behavior, excellent fatigue tolerance, high ionic conductivity (> 2.0 S m⁻ 1 ), and anti-freezing capability, which have not been achieved before. These properties allow the ionic hydrogel to operate as a stretchable multimodal sensor that can detect and decouple multiple stimuli (temperature, pressure, and proximity) with excellent discriminability, high sensitivity, and strong sensing-robustness against strains or temperature perturbations. The ionic hydrogel sensor exhibits great potential for intelligent electronic skin applications such as reliable health monitoring and accurate object identification.
危险品化学品经营许可证（带存储）