Enhanced Strain Resistance of Fractal Fiber Laser-Induced Graphene for Flexible Electrodes via Annealing and Plasma Etching

Laser-induced graphene (LIG) is a promising material for flexible and stretchable electronics due to its porous structure and high electrical conductivity. However, its mechanical fragility under strain limits practical applications. Here, we present a simple yet effective dual-treatment method, low-temperature annealing at 180°C followed by oxygen plasma etching—to enhance LIG's strain resistance. This process induces a dense fractal fiber network that preserves conductivity while improving structural stability. The treated LIG exhibits a reduced gauge factor (GF) of 7.43, approximately half that of untreated LIG, indicating lower sensitivity to strain-induced resistance changes. Scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses reveal improved fiber connectivity, enhanced graphitization, and reduced oxygen defects. The method is scalable, substrate-friendly, and well-suited for high-performance stretchable electronics.