Fatigue-Resistant\nPolystyrene Microsphere Nanoarray\nStrain Sensors Based on the PDMS Flexible Substrate

Flexible strain sensors have gained prominence in applications\nsuch as wearable devices, smart healthcare, and human motion monitoring\ndue to their excellent adaptability and sensitivity. However, challenges\nsuch as high production costs and complex fabrication processes hinder\ntheir widespread commercial adoption. This study presented a fatigue-resistant\npolystyrene (PS) microsphere nanoarray optical strain sensor based\non a polydimethylsiloxane flexible substrate, fabricated using a simple\nhemispherical indentation-assisted method. The sensor exhibited exceptional\nstability, enduring over 950 cycles, and demonstrated remarkable durability\nand sensitivity (−0.371 nm/%) at stretching speeds of 62.5\nμm/s. Finite element analysis, supported by the experimental\ndata, clarified the mechanical behavior of PS nanoarrays under varying\nstrain angles and analyzed the influence of these angles on the sensing\nspectrum. Besides, fatigue points caused by repeated use could be\nnaturally recovered, with the restored sensor maintaining excellent\nstability. The results suggested that this proposed flexible nanostructure\noffered a high-performance, cost-effective, and straightforward manufacturing\noption for strain optical sensors.