Ultrahigh sensitive, sensing-actuating integrated, and multi-functional intelligent skin based on electromechanical-hydraulic coupling

•A homogeneous sensing-actuating intelligent skin through 3D printing is presented.•A new strategy for realizing multifunctional wearable device through electro-mechanical-hydraulic coupling is presented.•An intelligent skin with an ultrahigh sensitivity of 1363.902 kPa−1 in 0–4 kPa is presented.•An intelligent skin with a real-time in-situ fluid-actuating response to external stimuli is presented.•An Intelligent skin with diverse capability induced by different functional fluids is presented. Electronic skin (e-skin) has great application prospects in the field of robots, smart medical care, and wearable electronics. However, the existing e-skin is far inferior to biological skin in intelligent response, which limits the miniaturization, intelligence, and versatility of e-skin. Herein, inspired by biological skin, an intelligent skin with a skin-like microchannel (SMC) structure, which can realize the sensing function of pressure and the actuating function of fluid simultaneously, is realized by using 3D printing. Due to the SMC structure, the intelligent skin has an ultrahigh sensitivity of 1363.9 kPa−1 in the pressure range of 0–5 kPa, which is superior to the existing E-skin. Uniquely, based on the mechanical-hydraulic coupling between fluid in SMC structure and external pressure, the intelligent skin has a real-time in-situ fluid-actuating intelligent response to external pressure, which enables the skin to realize a sensing-actuating integration without adding components. Moreover, with the sensing-actuating coupling characteristic, the skin can achieve diversified intelligent functions by introducing a variety of functional fluids into SMC structure, such as drug delivery, self-backup of sensing signal, and visual overload alarm. Besides, the realization of sensing-actuating integration in the intelligent skin provides a new strategy for the miniaturization and multi-functionalization of wearable devices.