Zhang Jia-Rui, Li Ang, Li Xi-Lin, Zhao Yi-Bo, Sun Jia-Shen, Guo Xiang-Xuan, Wang Wei, Liu Jiangen, Zhang Yong-Lai, Han Dong-Dong
State Key Laboratory of Integrated Optoelectronics, JLU Region, 2699 Qianjin Street, Changchun 130012, China.
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
ACS Appl Mater Interfaces. 2025 Mar 26;17(12):18940-18953. doi: 10.1021/acsami.5c01934. Epub 2025 Mar 13.
Flexible electronic circuits are critical in biomedical devices, human-machine interfaces, and wearable sensing systems, which further require flexible conductive materials with high conductivity, stretchability, and electrical stability. Liquid metal (LM) has attracted much attention due to its unique metallic conductivity and room-temperature fluidic properties. However, LM's high surface tension properties increase the difficulty of patterning processing. Here, we report a scalable and simple fabrication method based on femtosecond laser ablation for the facile fabrication of patterned LM and Cu composite electrodes (LM@Cu) on flexible substrates. The LM@Cu electrodes, fabricated utilizing the exceptional micro-nanoprocessing precision and three-dimensional fabrication capabilities of femtosecond lasers, exhibit high resolution (approximately 5 μm), superior electrical conductivity (4.08 × 10 S/cm), and enhanced stability. In addition to planar circuits, we successfully fabricated 3D-patterned LM@Cu electrode circuits on PDMS hemispheres. The presence of ultrathin copper foils significantly improves the wettability of LM on the substrate, and the occurrence of alloying reactions between LM and Cu circumvents the challenges posed by the high surface tension of LM in pattern fabrication. We further investigated the electromechanical properties of the patterned LM@Cu electrodes under twisting, bending, and stretching in detail. In addition, the LM@Cu electrodes serve as an interface between rigid electronic devices and flexible substrates. When suffering external damage, LM@Cu electrodes remain working after simple brush coating due to the excellent fluidity of LM. To explore this fabrication approach's potential, we demonstrate various applications in wearable electronics, including stretchable luminous wristbands, flexible wearable strain sensors, and "visible" thermotherapy panels for relieving aching joints.
柔性电子电路在生物医学设备、人机接口和可穿戴传感系统中至关重要，这进一步要求具备高导电性、可拉伸性和电气稳定性的柔性导电材料。液态金属（LM）因其独特的金属导电性和室温流体特性而备受关注。然而，液态金属的高表面张力特性增加了图案化加工的难度。在此，我们报告一种基于飞秒激光烧蚀的可扩展且简单的制造方法，用于在柔性基板上轻松制造图案化的液态金属与铜复合电极（LM@Cu）。利用飞秒激光卓越的微纳加工精度和三维制造能力制造的LM@Cu电极，具有高分辨率（约5μm）、优异的导电性（4.08×10 S/cm）和增强的稳定性。除了平面电路，我们还成功在聚二甲基硅氧烷（PDMS）半球上制造了三维图案化的LM@Cu电极电路。超薄铜箔的存在显著提高了液态金属在基板上的润湿性，并且液态金属与铜之间合金化反应的发生规避了液态金属在图案制造中高表面张力带来挑战。我们进一步详细研究了图案化的LM@Cu电极在扭曲、弯曲和拉伸下的机电性能。此外，LM@Cu电极充当刚性电子设备与柔性基板之间的接口。当遭受外部损坏时，由于液态金属出色的流动性，LM@Cu电极在简单刷涂后仍能继续工作。为了探索这种制造方法的潜力，我们展示了其在可穿戴电子产品中的各种应用，包括可拉伸发光腕带、柔性可穿戴应变传感器以及用于缓解关节疼痛的“可视”热疗面板。
