Flexible pressure sensors are currently at the center stage of wearable electronics. Despite tremendous progress in the recent years, flexible pressure sensors with high sensitivity, high stability, and mechanical robustness are still challenging. In this paper, as inspired by the bean pod structure, a sensor architecture consisting a microspacer core layer of polystyrene (PS) microspheres, sandwiched between two laser-induced graphene/polyurethane (LIG/PU) films, is presented. A flexible and self-healable pressure sensor is prepared, achieving ultrahigh sensitivity, improved linearity, wide sensing range up to 100 kPa, and excellent stability (for over 1000 loading−unloading cycles). Specifically, the pressure sensor achieves high sensitivities of 149, 659, and 2048 kPa −1 for the pressure ranges of 0−1, 1−10, and 10−100 kPa, respectively. Upon three cut−heal cycles at room temperature, severely damaged devices are self-healed and are able to maintain high sensitivity. The sensors have been further verified in stringent applications, such as human arterial pulse monitoring and gait detection. The novel device architecture enabling facile fabrication and high performance paves the way to the scalable production of pressure sensors for human physiological diagnostics and other advanced wearable applications.

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As compared to the traditional solid Janus particles, the hollow Janus particles have inspired growing interests due to their diverse potential applications. Herein, the novel hollow Janus particles with elephant trunk-like and acorn-like shapes were prepared by seed emulsion polymerization. In contrast to traditional template methods, the hollow structure was obtained during the preparation by one-step swelling method. The shapes and internal structures of hollow Janus particles were confirmed, and the compositions were identified too. Some critical influences on the morphology control were investigated, that is, the surface modification, the amount of surfactant, and cross-linking agent concentrations. It was inferred that the balance of hydrophilicity and hydrophobicity and the effective phase separation were important for preparing the hollow Janus particles with tailored shapes. Finally, amphiphilic properties of hollow Janus particles were demonstrated by emulsifying oil-water mixture.

Flexible gas sensors capable of working at room temperature are in great demand for the Internet-of-things (IoT) revolution. Although molybdenum disulfide (MoS 2 ) is a promising material for NO 2 gas sensing, the influence of morphology on sensing performance is not well understood. Existing gas sensors using conventional electrodes involve complex fabrication processes, resulting in high cost, thus severely limiting their ubiquitous application. In this paper, the design, fabrication, and characterization of MoS 2 gas sensors utilizing laser-induced graphene (LIG) electrodes are presented. Morphology evolution of MoS 2 nanostructures and the resulting gas sensing performance trade-offs are discussed. The flexibility and mechanical robustness of the sensors utilizing LIG electrodes have also been confirmed to be excellent. Overall, high performance in gas sensing combined with low susceptibility to mechanical damage enables the sensor to serve a variety of wearable sensory applications.

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