Multilayer flexible high-density liquid metal coils based on infusion

Given the urgent demand for flexibility in intelligent devices, liquid metals and flexible polymers have emerged as effective materials for the fabrication of flexible coils. However, the majority of current flexible coils show a single number of layers with sparse intra-layer structure, which impairs their sensing and actuation performance. Here, a multilayer high-density liquid metal coil (MHD-LMC) is introduced, which can be largely expanded by increasing the number of layers. Moreover, as the number of layer increases, MHD-LMC demonstrates excellent performance in both contact/non-contact sensing and actuation. As a pressure sensor, MHD-LMC is integrated into robot arm to distinguish pressing and sliding pattern. MHD-LMC can also detect a weak magnetic field as low as 50 μT, which enables it to detect the direction of electromagnetic field sources, such as a Helmholtz coil. Finally, MHD-LMC is utilized to fabricate a flexible electromagnetic pump, achieving a maximum flow rate of 11.35 mL min −1 and remaining its pumping performance under the pressed and bent conditions. In addition, the pump is capable of sensing its bending angle and subjected pressure. It provides the basis for expanding the application range of liquid metal-based complex flexible electronics, which holds significant potential for adoption in flexible robotics. • A universally applicable technique is proposed for fabricating multiple layers of interconnected coil channels in an elastic substrate. • The coil exhibits high flexibility and structural density with a powerful actuating force. • This coil integrates multiple capabilities: a multi-mode tactile sensor, a magnetic field source locator, and a flexible electromagnetic pump with a maximum flow rate of 11.35 mL min -1 .