Adaptive Morphology Control of Photo-Driven Lattice Flexible Sensor Arrays: Intelligent Contact Optimization for Wearable Physiological Signal Monitoring

Abstract

Flexible wearable sensors have demonstrated tremendous potential in personalized health monitoring, but their signal acquisition accuracy critically depends on the dynamically changing contact quality between the sensor and skin. Existing flexible sensors predominantly employ passive adaptation strategies, which struggle to actively optimize contact states in complex physiological scenarios such as motion and sweating, leading to signal quality degradation or even monitoring failure. To address this challenge, this study proposes an active morphology control method for flexible sensor arrays based on photo-driven lattice metamaterials. We constructed a truncated octahedral lattice structure with both high flexibility and photothermal responsiveness using poly(N-isopropylacrylamide)-single-walled carbon nanotube (PNIPAM-SWNT) hydrogel, and integrated conductive polymer (PEDOT:PSS) as sensing electrodes. Through precise scanning of 780nm femtosecond laser, local controllable deformation of the sensor array can be achieved. Experimental results show that the lattice structure design reduces the relative density of the sensor array to 18.5%, with photo-driven deformation amplitude reaching 35.2% and response speed of 12.8 μm/s. Through various morphology control modes such as local protrusion, bending, and torsion, the contact impedance between sensor and skin was effectively reduced by 62.3%, and the signal-to-noise ratio (SNR) of electrocardiogram (ECG) signals improved by 18.7 dB during motion states. This study innovatively extends photo-driven soft material technology from the microrobotics field to wearable electronics, providing a new paradigm for developing next-generation intelligent wearable devices with active adaptation capabilities, embodying deep interdisciplinary integration of design, materials, electronics, and biomedicine.