Ionic conductive hydrogels (ICHs) integrate the conductive performance and soft nature of tissue‐like materials to imitate the features of human skin with mechanical and sensory traits; thus, they are considered promising substitutes for conventional rigid metallic conductors when fabricating human‐motion sensors. However, the simultaneous incorporation of excellent stretchability, toughness, ionic conductivity, self‐healing, and adhesion via a simple method remains a grand challenge. Herein, a novel ICH platform is proposed by designing a phenylboronic acid‐ionic liquid (PBA‐IL) with multiple roles that simultaneously realize the highly mechanical, electrical, and versatile properties. This elaborately designed semi‐interpenetrating network ICH is fabricated via a facile one‐step approach by introducing cellulose nanofibrils (CNFs) into the PBA‐IL/acrylamide cross‐linked network. Ingeniously, the dynamic boronic ester bonds and physical interactions (hydrogen bonds and electrostatic interactions) of the cross‐linked network endow these hydrogels with remarkable stretchability (1810 ± 38%), toughness (2.65 ± 0.03 MJ m−3), self‐healing property (92 ± 2% efficiency), adhesiveness, and transparency. Moreover, the construction of this material shows that CNFs can synergistically enhance mechanical performance and conductivity. The wide working strain range (≈1000%) and high sensitivity (GF = 8.36) make this ICH a promising candidate for constructing the next generation of gel‐based strain sensor platforms.

Flexible sensors (FSs) are the key components of intelligent equipment and wearable devices, thus attracting increasing research interests in recent years. However, the preparation of multifunctional FS with good degradability in a natural environment is still challenging. In this work, we fabricated a flexible multimodal sensor that can detect multiple stimuli with only one device by spraying the mixture of carbon black (CB) and reduced graphene oxide (rGO) on a paper substrate. Scanning electron microscopy visualization indicated the CB particles absorbed on the surface of rGO, which then overlayered together, constructing a hierarchical structure. Benefiting from this unique structure, the obtained FS was demonstrated to have good sensitivity for strain, humidity, temperature, and pressure as well as multiple stimuli and was used to monitor human respirations as well as body motions, such as finger and elbow bending and head nodding. Besides, the sensor can be easily degraded in water being free of electronic pollution, but it also can be reused after the soaking–drying process, implying its reliability. This degradable and multimodal FS may find great potential in flexible electronics.

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Strict control of the size uniformity of carbon spheres is a prerequisite for many applications. However, there has been a long-standing challenge to design and synthesis of high-quality glucose-derived carbon spheres with outstanding size uniformity. In this Letter, we report a facile, sustainable, and chemical-additive-free method for the external pressure-assisted synthesis of monodisperse hydrothermal carbon spheres (MHCSs). The MHCSs obtained with the introduction of moderate pressure (2.0 MPa) exhibited good uniformity for carbon nanospheres (<100 nm) which can also be obtained by simply adjusting the external pressure.

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