Multi-responsive actuators driven by different stimuli (e.g. light, humidity, electricity) have attracted intense attention recently for the advantages of being used in various environments and show enormous actuation. In this work, we propose humidity- and light-driven actuators based on carbon nanotube (CNT)-coated paper and a biaxially oriented polypropylene (BOPP) composite. The CNT–paper/BOPP actuator shows large bending actuation when driven by humidity change (curvature of 1.2 cm⁻¹) and near infrared (NIR) light irradiation (curvature up to 1.6 cm⁻¹). The great actuation performances outperform most other paper-based actuators. Finally, a smart gripper, of which the initial opening width can be enlarged, is fabricated on the basis of the CNT–paper/BOPP actuators. By utilizing the bidirectional bending motion of the actuator, the opening width of the gripper can increase to a width that is 4 times larger than its initial width, so as to grasp a large object. The gripper is also able to raise and move an object that is 20 times heavier than one actuator of the gripper. We assume that this new type of actuator has great potential in artificial muscle, soft robotics and biomimetic applications.

Soft actuators with sensing capabilities are important in intelligent robots and human–computer interactions. However, present perceptive actuating systems rely on the integration of multiple functional units with complex circuit design. Here, a new‐type pressure‐perceptive actuator is reported, which integrates functions of sensing, actuating, and decision making at material level without complex combination. The actuator is composed of an actuating unit and a pressure‐sensing unit, both of which are fabricated by carbon nanotube (CNT), silk, and polymer composite. On the one hand, the actuating unit can be driven by low voltages (<13 V), owing to a Joule‐heating effect. On the other hand, the current passing the pressure‐sensing unit can be controlled by tactile pressure. In the integrated actuator, it is able to control the deformation amplitude of actuating unit by applying different pressures on the pressure‐sensing unit. A portable tactile‐activated gripper is fabricated to operate an object through pressure control, demonstrating its application in tactile soft robots. Finally, three visual logic gates (AND, OR, and NOT) are proposed, which convert “tactile” inputs into “visible” deformation outputs, using the CNT‐silk‐based material for sensing and actuating in the decision‐making process. This study provides a new path for intelligent soft robots and new‐generation logic devices.

Smart actuators integrated with sensing functions are taking a significant role in constructing intelligent robots. However, the detection of sensing signals in most actuators requires external electrical power, lacking in the self-powered feature. Herein, we report a graphene-based light-driven actuator with self-powered sensing function, which is designed by integrating a photo-thermoelectric generator into the actuator intelligently. When one part of the actuator is irradiated by near-infrared light, it shows a deformation with bending curvature up to 1.5 cm⁻¹, owing to the mismatch volume changes between two layers of the actuator. Meanwhile, the temperature difference across the actuator generates a voltage signal due to the photo-thermoelectric effect. The Seebeck coefficient is higher than 40 µV/K. Furthermore, the self-powered voltage signal is consistent with the deformation trend, which can be used to characterize the deformation state of actuator without external electrical power. We further demonstrate a gripper and a bionic hand. Their deformations mimic the motions of human hand (or finger), even making complex gestures. Concurrently, they can output self-powered voltage signals for sensing. We hope this research will pave a new way for self-powered devices, state-of-the-art intelligent robots, and other integrated multi-functional systems.

Multifunctionality has become a mainstream trend in the development of smart clothing and flexible wearable devices. Nevertheless, it remains a grand challenge to realize multiple functions, such as sensing, actuating and information displaying, in one single multifunctional material. Here, we present one multifunctional integration strategy by employing monolithic superaligned carbon nanotube (SACNT) composite, which can leverage three different functions through fascinating features of SACNT. Firstly, by using thermochromic dye as a color-memorizing component and SACNT as a photothermal converter, the composite film can be utilized as a flexible rewritable medium. It demonstrates excellent rewriting performances (reversibility > 500 times). Secondly, the composite can be tailored to fabricate an actuator, when its length direction is along the SACNT alignment. The actuator shows a bending-morphing when illuminated by near-infrared light. The morphing is attributed to a large difference in volume change between the SACNT and polymer when the SACNT absorbs the optical energy and heats the composite. Thirdly, owing to the unique anisotropy of SACNT, the composite is easily to be stretched in the direction perpendicular to the SACNT alignment, accompanied by a change in electrical resistance. Therefore, the composite is able to be used as a strain sensor. Finally, we fabricate two smart wearable devices to demonstrate the applications, which realize the functions of human-motion detection (sensing) and rewritable information display (rewriting) simultaneously. This multifunctional SACNT composite is expected to have potential applications in the next-generation wearable devices, smart clothing and so on.

With the development of science and technology, wearable electronics are increasingly widely used in medical, environmental monitoring, and other fields. Thus, the demand for flexible electrodes is increasing. The two-dimensional material Ti₃C₂T_x has attracted much attention in the manufacture of flexible electrodes due to its excellent mechanical and electrical properties. However, the brittleness of pure Ti₃C₂T_x films has become a major obstacle for their use as flexible electrodes in wearable devices. Therefore, solving the brittleness problem of flexible electrodes based on Ti₃C₂T_x while maintaining the excellent performance of Ti₃C₂T_x has become an urgent problem. To solve this problem, Ti₃C₂T_x was compounded with waterborne polyurethane (WPU), and a Ti₃C₂T_x-WPU composite film with a hierarchical structure was constructed by evaporation-assisted self-assembly. The Ti₃C₂T_x-WPU composite film not only retains the excellent electrical conductivity of Ti₃C₂T_x (100 S m⁻¹) but also has flexibility (20 MJ m⁻³). Furthermore, the Ti₃C₂T_x-WPU composite film is applied to functional devices such as contact pressure sensors and non-contact proximity sensors. Finally, the Ti₃C₂T_x-WPU composite film wearable device demonstrates its practical application potential in the field of wearable devices.