Researchers transform natural leather into an electronic skin that combines pressure sensing, thermal regulation, and impact protection in a flexible format.
(Nanowerk Spotlight) Flexible electronics are reshaping how humans interact with machines, creating new possibilities for systems that conform to the body and respond intelligently to physical stimuli. Among the most ambitious goals in this field is the development of electronic skin—e-skin—that replicates the sensory and protective functions of biological tissue.
Real skin does more than just sense touch; it buffers mechanical impacts, regulates temperature, and shields the body from harmful radiation. Replicating all these functions in a single synthetic material has proven technically complex. Most artificial skins focus narrowly on pressure sensing or surface temperature monitoring, often falling short when required to provide mechanical robustness or electromagnetic shielding.
A variety of material systems have been explored in pursuit of a true e-skin, including hydrogels, silicone elastomers, carbon nanotube composites, and layered polymer matrices. While many of these have achieved impressive sensitivity to pressure or temperature, their mechanical fragility, structural instability, or limited responsiveness under stress have restricted their practical use. Some efforts have turned to bio-derived substrates like cellulose or silk. Although lightweight and flexible, these materials are often fragile and lack the structural hierarchy needed for reliable multifunctionality.
Leather—processed animal skin—presents an intriguing alternative. It possesses intrinsic toughness, flexibility, and a multilayered collagen fiber structure that resembles the dermal framework of natural skin. Its use in clothing and protective gear underscores its reliability.
However, until now, efforts to adapt leather for flexible electronics have been hampered by poor structural integration, limited sensitivity under dynamic conditions, and weak electromagnetic shielding. These limitations have prevented leather from advancing beyond a passive substrate into a truly intelligent material capable of emulating skin’s full range of functions.
In a study published in Advanced Functional Materials (“Exceed the Traditional Dead Leather to Intelligent E‐Skin”), researchers from the University of Science and Technology of China and Hong Kong Baptist University present a leather-based composite that addresses these limitations. By integrating silver nanostructures and a viscoelastic polymer into natural leather, the team developed a multifunctional e-skin that unites pressure sensing, thermal control, impact protection, and electromagnetic shielding in a single material platform.
This composite, referred to as LAP (Leather/Ag/Polyborosiloxane Elastomer), mirrors the layered anatomy of human skin. The leather forms the outer protective surface, analogous to the epidermis. Embedded within this layer is a hybrid network of silver nanowires and silver flakes. These fill the gaps between collagen fibers, creating a dense, conductive network that functions like the skin’s dermis. The inner layer comprises a polyborosiloxane elastomer—a viscoelastic material that stiffens upon impact, much like the hypodermis’ role in absorbing mechanical shocks.
Preparation process and mechanism of sensing and protection of LAP. a) The schematic fabrication of LAP E-skin. b) The layered structure of natural human skin. c) The multi-layer structure of LAP E-skin. The sensing mechanism of LA and buffering mechanism of PBSE. d) Optical images of LAP E-skin:(i) outer side, (ii) inner side, (iii) folding, and (iv) attaching to wrist. (Image: Reprinted with permission by Wiley-VCH Verlag) (click on image to enlarge)
The conductive layer benefits from the combination of one-dimensional nanowires and two-dimensional flakes. The flakes act as broad conductive platforms while the nanowires link them, forming a three-dimensional network. This arrangement significantly enhances conductivity and mechanical cohesion. The optimal ratio of silver nanowires to flakes—determined to be 1:2—yielded both low resistance and high tensile strength. The material reached a tensile strength of 9.28 MPa at a silver content of 5.0 mg/cm², nearly doubling the strength of the underlying leather-polymer base. Fracture strains of up to 70.8% demonstrate the composite’s flexibility and capacity for wearable use.
Thermal performance is equally notable. When voltage is applied across the material, it heats rapidly and uniformly, reaching a surface temperature of 110°C within 5 minutes at 3.0 volts. The heating response is stable over repeated cycles and correlates linearly with input power. This precise electrothermal control makes the LAP e-skin suitable for therapeutic heating or cold-weather protection.
The material also provides high electromagnetic interference (EMI) shielding. Shielding effectiveness reached approximately 75 dB in the 8.2–12.4 GHz range (X-band), well above the 20 dB threshold typically required for commercial EMI protective materials. This performance stems from both reflection and absorption mechanisms. The hierarchical structure of leather fibers and the interwoven silver network produce multiple internal reflections and conductive losses, dissipating electromagnetic energy efficiently as heat. The material retained most of its shielding performance even after 1000 cycles of bending and stretching.
Mechanical protection is another core feature. The inner polyborosiloxane elastomer displays rate-dependent stiffness—it remains soft during slow deformation but hardens under high-speed impacts. This behavior is governed by reversible chemical bonds in the polymer that respond dynamically to stress. Under controlled impact testing, the LAP e-skin absorbed over 85% of impact energy and reduced transmitted peak force by nearly 47%. Its buffering performance held steady across varying impact angles and velocities, confirming its potential for wearable protection.
One of the most distinctive capabilities of the LAP e-skin is its dual-mode sensing response. Under slow compression, the conductive network densifies, reducing resistance and enabling precise piezoresistive sensing. The sensor detected strains as low as 2% with consistent signal output over 500 cycles. Under high-speed impact, however, the network momentarily fractures, increasing resistance instead. This difference allows the material to distinguish between light contact and sudden impacts, a feature that mimics how real skin perceives touch versus pain.
To translate this functionality into a wearable format, the team developed a smart vest embedding the LAP e-skin into a 5×5 sensor array. The vest supports real-time pressure mapping, shape recognition, and controlled heating across multiple zones. When integrated with a Bluetooth module, it transmits sensor data wirelessly and triggers alerts if impacts exceed a threshold. The system offers real-time monitoring suitable for protective clothing in hazardous environments.
Practical evaluations showed the LAP material is skin-compatible and mechanically robust. No irritation was observed after 24 hours of continuous skin contact, and the material retained function after thermal aging and repeated mechanical cycling. Even after artificial aging at elevated temperature and humidity, the material’s resistance and EMI performance remained within operational limits.
This study illustrates how biologically inspired materials can be reengineered to achieve functional integration across sensing, protection, and regulation domains. The choice to reconfigure leather—already optimized by evolution for wearability and toughness—provides a structurally rich and mechanically resilient platform. By layering conductive and responsive components onto this substrate, the researchers have constructed a versatile material that pushes the capabilities of e-skin systems toward those of natural tissue.
The LAP e-skin addresses multiple practical needs in a single configuration. It protects against impact, senses pressure, regulates temperature, and shields against electromagnetic radiation—without sacrificing flexibility or comfort. This convergence of properties makes it particularly suitable for applications in healthcare, occupational safety, military gear, and soft robotics, where simultaneous performance in diverse conditions is essential.
As efforts in wearable technology evolve, the demand for materials that replicate both the structure and function of living systems will continue to grow. This work underscores the potential of combining traditional materials like leather with nanoscale engineering and responsive polymers to meet that challenge, setting a new benchmark for multifunctional e-skin development.
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