Gas-Permeable, Ultrathin, Stretchable Epidermal Electronics with Porous Electrodes

Abstract

We present gas-permeable, ultrathin, and stretchable electrodes enabled by self-assembled porous substrates and conductive nanostructures. An efficient and scalable breath figure method is employed to introduce the porous skeleton, and then silver nanowires (AgNWs) are dip-coated and heat-pressed to offer electric conductivity. The resulting film has a transmittance of 61%, sheet resistance of 7.3 Ω/sq, and water vapor permeability of 23 mg cm–2 h–1. With AgNWs embedded below the surface of the polymer, the electrode exhibits excellent stability in the presence of sweat and after long-term wear. We demonstrate the promising potential of the electrode for wearable electronics in two representative applications: skin-mountable biopotential sensing for healthcare and textile-integrated touch sensing for human–machine interfaces. The electrode can form conformal contact with human skin, leading to low skin–electrode impedance and high-quality biopotential signals. In addition, the textile electrode can be used in a self-capacitance wireless touch sensing system.

Fully Fabric-Based Triboelectric Nanogenerators as Self-Powered Human–Machine Interactive Keyboards

“…With the development of flexible human–machine interface devices, intensive progress has been realized by utilizing deformable conductors [ 25 , 26 ], stretchable sensors [ 27 , 28 ], or flexible films [ 29 – 31 ]. However, polymer substrates, such as polyethylene terephthalate (PET), polyimide (PI), and polydimethylsiloxane (PDMS), were used for most flexible human–machine interface devices [ 32 , 33 ], have the disadvantage of low fit and unsatisfying comfort for human body.…”

Recent Advances in Nanomaterial‐Enabled Wearable Sensors: Material Synthesis, Sensor Design, and Personal Health Monitoring

“…For example, Zhou et al reported a gas‐permeable, ultrathin, and stretchable ECG sensor. [ 132 ] As demonstrated in Figure , thermoplastic polyurethane (TPU)–polyethylene glycol (PEG) mixed solution was coated on the glass slides and placed in a chamber with high humidity (relative humidity: 99%). Then, water molecules were first condensed on the surface of TPU–PEG film and then merged to water droplets.…”

Interface Design for Stretchable Electronic Devices

“…Zhou et al presented gas-permeable, stretchable electrode using porous thermoplastic polyurethane (TPU) and Ag NWs (Figure 17f). [184] The porous TPU film was prepared by the breath figure method to have the pore diameter of 40 µm and pore coverage of about 39%. Ag NWs were hot pressed over this porous TPU to be embedded in the polymer surface.…”

“…Reproduced with permission. [ 184 ] Copyright 2020, American Chemical Society. g) Hygroscopic auxetic on‐skin sensor electrode using a serpentine‐structured PEGDA hydrogel.…”