A Generic Strategy to Create Mechanically Interlocked Nanocomposite/Hydrogel Hybrid Electrodes for Epidermal Electronics

Stretchable electronics are crucial enablers for next-generation wearables intimately integrated into the human body.As the primary compliant conductors used in these devices,metallic nanostructure/elastomer composites often struggle to form conformal contact with the textured skin.Hybrid electrodes have been consequently developed based on conductive nanocomposite and soft hydrogels to establish seamless skin-device interfaces.However,chemical modifications are typically needed for reliable bonding,which can alter their original properties.To overcome this limitation,this study presents a facile fabrication approach for mechanically interlocked nanocomposite/hydrogel hybrid electrodes.In this physical process,soft microfoams are thermally laminated on silver nanowire nanocomposites as a porous interface,which forms an interpenetrating network with the hydrogel.The microfoam-enabled bonding strategy is generally compatible with various polymers.The resulting interlocked hybrids have a 28-fold improved interfacial toughness compared to directly stacked hybrids.These electrodes achieve firm attachment to the skin and low contact impedance using tissue-adhesive hydrogels.They have been successfully integrated into an epidermal sleeve to distinguish hand gestures by sensing mus-cle contractions.Interlocked nanocomposite/hydrogel hybrids reported here offer a promising platform to combine the benefits of both materials for epidermal devices and systems.

Fully solution processed liquid metal features as highly conductive and ultrastretchable conductors

Liquid metal represents a highly conductive and inherently deformable conductor for the development of stretchable electronics.The widespread implementations of liquid metal towards functional sensors and circuits are currently hindered by the lack of a facile and scalable patterning approach.In this study,we report a fully solution-based process to generate patterned features of the liquid metal conductor.The entire process is carried out under ambient conditions and is generally compatible with various elastomeric substrates.The as-prepared liquid metal feature exhibits high resolution(100μm),excellent electrical conductivity(4.15×10^(4)S cm^(−1)),ultrahigh stretchability(1000%tensile strain),and mechanical durability.The practical suitability is demonstrated by the heterogeneous integration of light-emitting diode(LED)chips with liquid metal interconnects for a stretchable and wearable LED array.The solution-based technique reported here is the enabler for the facile patterning of liquid metal features at low cost,which may find a broad range of applications in emerging fields of epidermal sensors,wearable heaters,advanced prosthetics,and soft robotics.