Materials, Structures, and Functions for Flexible and Stretchable Biomimetic Sensors.

Currently, flexible and stretchable biomimetic sensing electronics have obtained a great deal of attention in various areas, such as human-machine interfaces, robotic smart skins, health care monitoring, and biointegrated devices. In contrast with the traditional rigid and fragile silicon-based electronics, flexible and stretchable sensing electronics can efficiently capture high-quality signals when integrated on curved surfaces due to their elastic and conformal characters, which are expected to play many important roles in the foreseeable age of intelligence. Its realization strongly relies on rapid advances in the development of high-performance and versatile flexible and stretchable sensors, and effective ways to achieve high performance are rational designs of the sensing materials and microstructural configurations. This Account showcases the recent progress in flexible and stretchable biomimetic sensors covering several critical aspects of materials, structures, and applications. Nature-inspired active matter and architectures, which have been well-tuned by evolution through millions of years of optimization, provide us the best learning choices to overcome the restrictions of current sensor techniques such as low sensitivity, instability, and delayed response time. Biomimetic sensing materials and microstructural patterns can efficiently acquire synthetic response abilities, endowing the new-type flexible sensors considered as "smart" electronic components on account of the counterparts to living organisms. Moreover, the developments of diverse functions and multifunctional applications become more and more important in the creation of novel flexible electronics beyond those existing technologies. For instance, flexible and stretchable sensors with the capability of mimicking various human behavioral patterns can be developed to boost the emergence of artificial robots, which can take the place of human beings in strenuous activities, enabling progress in social science, technology, and productivity to improve the quality of human life. For the above purpose, inspired by the in-depth understanding of working principles of living organisms how to operate their natural characteristics, sensing materials with stimuli response (light, humidity, mechanics, etc.) and multifunctionalities (superhydrophobicity, degradation, self-healing, etc.) provide distinctive and multiple detection features generally encountered in their traditional counterparts. In addition, artificial micro- to nanostructures derived from naturally existing high sensitivity structures (such as insect crack or leaves) and stretchable configurations (wrinkle, texture, mesostructures, etc.) offer additional feasible strategies for producing favorable sensitivity and stretchability. Flexible and stretchable biomimetic sensors with analogous senses to those of human beings (such as tactile and auditory senses) have attracted tremendous attention for their diverse applications for next generation smart electronics. The long-term progress of these novel sensors influencing the next generations of bioinspired intelligence systems and medical electronics are also envisioned.