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An intrinsically stretchable rubbery semiconductor with high mobility is critical to the realization of high-performance stretchable electronics and integrated devices for many applications where large mechanical deformation or stretching is involved. Here, we report fully rubbery integrated electronics from a rubbery semiconductor with a high effective mobility, obtained by introducing metallic carbon nanotubes into a rubbery semiconductor composite. This enhancement in effective carrier mobility is enabled by providing fast paths and, therefore, a shortened carrier transport distance. Transistors and their arrays fully based on intrinsically stretchable electronic materials were developed, and they retained electrical performances without substantial loss when subjected to 50% stretching. Fully rubbery integrated electronics and logic gates were developed, and they also functioned reliably upon mechanical stretching. A rubbery active matrix based elastic tactile sensing skin to map physical touch was demonstrated to illustrate one of the applications. 

Stretchable electronics outperform existing rigid and bulky electronics and benefit a wide range of species, including humans, machines, and robots, whose activities are associated with large mechanical deformation and strain. Due to the nonstretchable nature of most electronic materials, in particular semiconductors, stretchable electronics are mostly realized through the strategies of architectural engineering to accommodate mechanical stretching rather than imposing strain into the materials directly. On the other hand, recent development of stretchable electronics by creating them entirely from stretchable elastomeric electronic materials, i.e., rubbery electronics, suggests a feasible a venue. Rubbery electronics have gained increasing interest due to the unique advantages that they and their associated manufacturing technologies have offered. This work reviews the recent progress in developing rubbery electronics, including the crucial stretchable elastomeric materials of rubbery conductors, rubbery semiconductors, and rubbery dielectrics. Thereafter, various rubbery electronics such as rubbery transistors, integrated electronics, rubbery optoelectronic devices, and rubbery sensors are discussed.

 

The architecture of stretchable electronics, typically in the fashion of very thin functional electronics on a stretchable rubber substrate, defines their mechanical robustness which is dominantly attributed to the stretchable rubber substrate. Most of the existing and reported stretchable electronics are vulnerable to flaws or cracks in the substrate and subject to fracture upon mechanical deformation, which limits their practical usages. Here, a class of tough and flaw insensitive stretchable electronics enabled by a Nylon/rubber composite substrate is reported. The woven and stretchable fibers in the Nylon fabric are responsible for its high toughness and flaw insensitivity, as they prevent crack propagation by dissipating the energy into the nearby fiber network and also the rubber matrix to yield enhanced toughness and flaw insensitivity. Stretchable electrodes, supercapacitors, and photodetectors with high toughness and flaw insensitivity are developed as examples to illustrate the validity of such a type of stretchable electronics. Systematic studies of the associated materials, fabrication, mechanical and electrical properties, and reliability illustrate the key aspects of such a type of stretchable tough and flaw insensitive electronics and also suggest routes toward stretchable electronics with other functions.

 

Soft robots outperform the conventional hard robots on significantly enhanced safety, adaptability, and complex motions. The development of fully soft robots, especially fully from smart soft materials to mimic soft animals, is still nascent. In addition, to date, existing soft robots cannot adapt themselves to the surrounding environment, i.e., sensing and adaptive motion or response, like animals. Here, compliant ultrathin sensing and actuating electronics innervated fully soft robots that can sense the environment and perform soft bodied crawling adaptively, mimicking an inchworm, are reported. The soft robots are constructed with actuators of open‐mesh shaped ultrathin deformable heaters, sensors of single‐crystal Si optoelectronic photodetectors, and thermally responsive artificial muscle of carbon‐black‐doped liquid‐crystal elastomer (LCE‐CB) nanocomposite. The results demonstrate that adaptive crawling locomotion can be realized through the conjugation of sensing and actuation, where the sensors sense the environment and actuators respond correspondingly to control the locomotion autonomously through regulating the deformation of LCE‐CB bimorphs and the locomotion of the robots. The strategy of innervating soft sensing and actuating electronics with artificial muscles paves the way for the development of smart autonomous soft robots.