Soft electronics application refers to the utilization of flexible, stretchable, and conformable electronic devices in various fields and industries. Unlike traditional rigid electronics, soft electronics are designed to mimic the properties of natural materials, such as human skin, making them comfortable to wear and able to seamlessly integrate with the body or other soft surfaces. Skin electronics are a set of skin-mounted devices whose mechanical properties are comparable to those of human skin. They have been deployed in various applications such as biomedical devices, human-computer interfaces, and virtual or augmented reality devices.

One of the vital components for skin electronics is the ultrathin elastic conductor, and conductive elastic nanocomposites have been considered as a feasible candidate. However, critical challenges still remain, including metallike conductivity, high stretchability, ultrathin thickness, and facile patternability. Typically, there are trade-offs between these properties, and these goals have hardly been achieved at the same time. We developed a novel method, using float assembly, to create a nanomembrane for skin electronics that combines metallike conductivity, high stretchability, ultrathin thickness, and easy patterning. This method enables compact assembly of nanomaterials at the water-oil interface, resulting in a nanomembrane that maintains high elasticity even with a high loading of nanomaterials. Additionally, the structure allows for cold welding and bilayer stacking, preserving high conductivity even after high-resolution patterning, making it suitable for creating multifunctional epidermal sensor arrays.