Flexible wearable electronics have attracted great attention due to their extensive applications in health monitoring, intelligent clothing, etc. The substrate of most wearable electronics is commercial polymers, biopolymers, and fabrics. These substrates have some shortcomings, such as air-impermeability and being non-waterproof. Leather is a natural material with a natural hierarchical structure, which possesses the unique advantages of breathability, water resistance, and biodegradability, enabling it to be a promising substrate for wearable electronics. Although leather-based wearable electronics have been developed, it is still a challenge to integrate multiple functions in a single leather-based electronic device due to the different working mechanisms of various functions. Here, multi-functional reduced graphene oxide/leathers (RGO/leathers) for versatile wearable electronics are fabricated by vacuum filtration of GO dispersions, in situ reduction of GO/leather, and painting thermochromic ink. The RGO/leathers are characterized by low sheet resistance (90 Ω □⁻¹), large fracture strain (91%), and air permeability, which are due to the tight intertwining and extensive hydrogen bond interaction between RGO and collagen fibers. Thus, the performances of electrical heating, output of the triboelectric nanogenerators (TENGs), and electromagnetic interference (EMI) shielding of RGO/leather are first investigated in detail. The electric-to-thermal conversion efficiency of the RGO/leather with different RGO contents is over 80%. The output of the RGO/leather-based TENG based on the contact-separation mode is stable at 80 V. Also, the EMI shielding effectiveness of RGO/leather is over 23 dB, which exceeds the target value required for commercial products. Subsequently, the wearable applications of the RGO/leather are demonstrated, such as electrically driven personal thermal management devices (kneepads), wearable dry electrodes (to collect electrophysiological signals), self-powered material identification, and EMI shielding pockets. In summary, versatile wearable electronics can be fabricated based on RGO/leather through a green and gentle approach. RGO/leather provides a new platform for the fabrication of air-permeable and sustainable wearable electronics, broadening the application prospects of natural polymer materials in wearable electronics.

Wearable conductive hydrogel sensors, which are highly convenient, have attracted attention for their great potential in human motion monitoring and smart healthcare. However, the self−adhesive properties, sensing performance, and stability of traditional hydrogels are not ideal, which seriously hinders their use in monitoring and diagnosing joints throughout the human body. Here, CaCl₂ is used to crosslink PVA to improve its self−adhesive properties, and it is then combined with a CNT conductive network. Next, a cyclic freeze–thaw strategy is utilized to fabricate a wearable PVA−Ca−CNT hydrogel with excellent self-adhesive properties and stability. PVA−Ca−CNT hydrogels can adhere to various substrates, with a maximum self-adhesion strength of 398 kPa and a unit adhesion energy of as high as 305 μJ cm⁻². Furthermore, the CNT three−dimensional network enhances the tensile strength to 110 kPa, with almost no hysteresis. Based on resistance changes, PVA−Ca−CNT hydrogel exhibits a sensitivity of up to 11.11 as a strain sensor as well as a response to strain stimuli within 180 ms. When PVA−Ca−CNT hydrogel is adhered to the surface of human skin, it operates as a sensor for monitoring human movement. Not only can it accurately monitor the movement positions of major joints in the human body, it can also accurately identify tiny movements of the fingers and be used as a finger Morse code output device, which demonstrates the enormous potential of human motion monitoring systems based on self−adhesive hydrogel sensors in practical applications.

Self‐assembly of three‐dimensional (3D) structures, through bending, twisting, folding, and buckling, has garnered broad interest among physicists, mathematicians, chemists, and biologists. Herein strain engineering and geometric frustration as an on‐demand strategy for fabricating spontaneous rolling “origami” structures with programmable multistability across multiple length scales are exploited. Through experiments, theory, and finite element simulations, it is demonstrated that a strain‐engineered bilayer structure can make a transition from a monostable, doubly curved shape to a neutrally stable, developable configuration, depending on a dimensionless parameter that is determined through the plate's geometry and misfit strain. In addition, the doubly curved region near the edge can play a significant role in deciding the final bending direction of the strained bilayer due to edge effects. A strain‐engineering approach is further proposed to generate various 3D structures by programming the geometry, misfit strain, and mechanical properties of the bilayer units, for instance, a self‐folding buckyball structure. These design principles have promising broad applications in constructing self‐deploying, stimuli‐responsible, and multifunctional devices across multiple length scales.