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Human skin comprises multiple hierarchical layers that perform various functions such as protection, sensing, and structural support. Developing electronic skin (E‐skin) with similar properties has broad implications in health monitoring, prosthetics, and soft robotics. While previous efforts have predominantly concentrated on sensory capabilities, this study introduces a hierarchical polymer system that not only structurally resembles the epidermis‐dermis bilayer structure of skin but also encompasses sensing functions. The system comprises a polymeric hydrogel, representing the "dermis", and a superimposed nanoporous polymer film, forming the "epidermis". Within the film, interconnected nanoparticles mimic the arrangement of interlocked corneocytes within the epidermis. The fabrication process employs a robust in situ interfacial precipitation polymerization of specific water‐soluble monomers that become insoluble during polymerization. This process yields a hybrid layer establishing a durable interface between the film and hydrogel. Beyond the structural mimicry, this hierarchical structure offers functionalities resembling human skin, which includes (1) water loss protection of hydrogel by tailoring the hydrophobicity of the upper polymer film; (2) tactile sensing capability via self‐powered triboelectric nanogenerators; (3) built‐in gold nanowire‐based resistive sensor toward temperature and pressure sensing. This hierarchical polymeric approach represents a potent strategy to replicate both the structure and functions of human skin in synthetic designs. [ABSTRACT FROM AUTHOR]

Electronic skin (E-skin) capable of detecting various physical stimuli is required for monitoring external environments accurately. Here, we report an all-soft multiaxial force sensor based on liquid metal microchannel array for electronic skin applications. The proposed sensor is composed of stretchable elastomer and Galinstan, a eutectic gallium-indium alloy, providing a high mechanical flexibility and electro-mechanical durability. Liquid metal microchannel arrays are fabricated in multilayer and positioned along a dome structure to detect multi-directional forces, supported by numerical simulation results. By adjusting the height of the dome, we could control the response of the multiaxial sensor with respect to the deflection. As a demonstration of multiaxial force sensing, we were able to monitor the direction of multidirectional forces using a finger by the response of liquid metal microchannel arrays. This research could be applied to various fields including soft robotics, wearable devices, and smart prosthetics for artificial intelligent skin applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Investigation of self-healing polymers for electronic-skin devices. • Overview of recent self-healing polymeric electronic skin advances. • Understanding of the thermodynamic contribution for self-healing fibrous network. • Conceptualization for electrospun self-healing breathable electronic skin. The development of wearable soft electronic skins requires the production of materials with high mechanical flexibility, an inherent self-healing mechanism, and high breathability. Autonomous self-healing mechanisms have been widely investigated to produce materials that can continue operating in hostile environments or after sustaining damage. However, mimicking the functions of natural human skin requires breathability. Given the thermodynamic considerations of the self-healing process and self-healing polymers, achieving porosity in such materials is a major challenge. Electronic skins fabricated through electrospinning have mechanical flexibility, breathability, and high overall performance; however, most electrospun self-healing fibrous materials have an extrinsic healing mechanism. Therefore, the further development of intrinsic healing methods is essential for the maturation of fibrous electronic skin technology. Several challenges must be addressed before the next generation of electronic skin devices can be developed. This review aims to discuss the shortcomings of current electronic skins and suggests several paths for developing fully self-healing and breathable electronic skins for future soft robotics and human–machine interfaces. [ABSTRACT FROM AUTHOR]