Strain‐Adaptive Liquid Metal Interfaces Overcome Poisson's Ratio Constraints in Piezoresistive Sensors for Infant Sleep Monitoring

作者：Yuxiao Zhang, Chenchen Wang, Juan Tao, Siyue Ma, Siyu Xie, Weiwei Guo, Rongrong Bao, Jianbei Qiu, Yue Liu, Zhengwen Yang, Caofeng Pan · 发表于：Advanced Science · 年份：2025 · DOI：10.1002/advs.202515117 · 被引用次数：4 · 研究领域：Advanced Sensor and Energy Harvesting Materials、Tactile and Sensory Interactions、Modular Robots and Swarm Intelligence

Abstract Conventional porous piezoresistive sensors suffer from lateral expansion due to a positive Poisson's ratio, causing conductive network fracture and unreliable signals. Existing structural solutions are limited by high costs and poor durability. This study introduces a dynamic conductive interface mechanism using liquid metal (LM) ink to bypass Poisson's ratio limitations. By coating eutectic gallium‐indium (EGaIn) onto a hydrophilic porous thermoplastic polyurethane (TPU) scaffold, a strain‐adaptive conductive layer is constructed, where LM droplets directionally flow to fill microcracks during deformation. This mechanism retains 98.73% of initial conductive pathways under 98% tensile strain, achieving ultra‐high sensitivity (693.65 kPa −1 , 0.32‐10.24 kPa). The LM‐based sensor demonstrates intrinsic antibacterial properties and launderability. Integrated into an intelligent infant pillow with a 16‐chanels sensor array, the system enables real‐time cephalic pressure monitoring and edge‐computed posture correction via a companion app. This work proposes a material‐mechanics co‐design strategy to overcome Poisson ratio constraints, advancing high‐performance, scalable wearable biomedical devices.