Permeable Conductors for Wearable and On‐Skin Electronics

Abstract

The booming development of wearable and on‐skin electronics has driven increased interest in flexible and stretchable conductors, which serve as the indispensable building blocks for these electronic devices. However, conductors for such soft electronics are mostly fabricated with impermeable elastic thin films, which not only affect the long‐term wearing comfort but also limit the device's multifunctionality. In recent years, permeable conductors, conducting materials that are fabricated based on breathable materials and structures with deformability, have shown great promise for applications in wearable and skin‐mountable electronics. Herein, a specific perspective on the development of permeable conductors that can simultaneously display conductivity, flexibility or stretchability, and permeability to air, moisture, and liquid is provided. Key design considerations of permeable conductors, as well as the state‐of‐the‐art strategies to endow flexible and stretchable conductors with permeability, are discussed. Finally, key challenges and future directions of permeable conductors and electronic devices are discussed along with the analysis of possible solutions.

Skin bioelectronics towards long-term, continuous health monitoring

“…Although many current skin bioelectronics are based on a low-permeability film-type form factor, a health microenvironment allows the human skin to 'breathe', that is, there is sufficient permeability to air, water vapour, and liquid. 210,211 To realise the full potential of long-term health monitoring, breathability is one of the key features to target for skin bioelectronics. 59,212 Breathable electronic devices also improve the biocompatibility of skin electronic devices because they do not cause inflammation and are gas-permeable.…”

Printable and Highly Stretchable Viscoelastic Conductors with Kinematically Reconstructed Conductive Pathways

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represent the cornerstone of next-generation electronics. [1][2][3] They are promising for skin electronics, [4][5][6] soft robotics, [7,8] medical implants, [9,10] and human-machine interfaces. [11][12][13][14] Thus far, most stretchable electronics are fabricated by integrating active components including sensors, actuators, transistors, and optoelectronic devices with stretchable interconnections onto soft, stretchable substrates to ensure levels of integration, performance, and reliability comparable to those of waferbased systems.

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Rechargeable Micro‐Batteries for Wearable and Implantable Applications

“…At present, a variety of wearable and portable consumer electronics have been widely utilized such as mobile phones, Apple Watch, Google Glass, and Xiaomi band. [60][61][62][63] Meanwhile, many novel wearable microelectronics are on the way and will enter our lives soon, [4,64] which brings higher requirements for corresponding high-performing micro-power sources. Typically, these energy-storage devices need to be miniature, lightweight, flexible, and safe.…”