Laser-induced reduction is widely used to modify graphene oxide, yet the chemical origin of fatigue degradation induced by such processing remains poorly understood. Here, we show that Raman laser irradiation acts not only as a characterization tool but also as a controllable reduction stimulus. Combined Raman and nano-infrared spectroscopy reveal that laser exposure preferentially removes sp³-type oxygen functional groups, particularly epoxide groups, while vacancy-type defects progressively accumulate. Atomic force microscopy-based fatigue experiments further demonstrate that laser-reduced graphene oxide exhibits inferior fatigue resistance compared to oxidized samples. This degradation arises from the combined effects of vacancy accumulation and the loss of epoxide-enabled crack-arresting mechanisms, driving a transition from localized damage to brittle fracture. These findings establish that fatigue reliability in graphene oxide is governed by chemical identity and defect evolution history, rather than defect density alone, highlighting the limitations of single-parameter Raman metrics for predicting mechanical performance in functionalized two-dimensional materials.

Transient high friction force usually appears when a hard sphere slides on a soft substrate during the water evaporation. Such a special wetting condition featuring the friction enhancement, even exceeding the friction of dry conditions, is termed as tacky regime. Herein, the impact of Schallamach waves on the friction enhancement induced by capillary adhesion is investigated by integrating microtribometer measurements, interference microscopy visualization, and finite element analysis. The friction peak decreases or even disappears with decreasing elastic modulus of the soft substrate, which is attributed to the nucleation and propagation of Schallamach waves. The increase in friction during the tacky transition depends on the competition between capillary adhesion and stress relief of Schallamach wave.