Wireless bubble detection enabled by triboelectric discharge

Bubble detection plays a crucial role in various industrial applications. Precise bubble detection can help improve safety and prevent accidents, e.g., heat transfer deterioration, flow instability, and pernicious air injection. Herein, we proposed a self-powered wireless bubble detection strategy induced by triboelectric energy conversion, which exerted a negligible impact on bubble movement and did not require the elimination of the near-wall liquid film. The rotation free-standing triboelectric nanogenerator (RF-TENG) provided an alternating high-voltage source to activate the air breakdown between the tip-to-tip probe. The breakdown time when the bubble crossed the probe represented the bubble duration and length. The robust linear relationships among the detection parameters under stationary deionized water, solutions with varied viscosities, and flowing conditions were demonstrated. A wireless transmission performance with a long distance of over 8.3 m was achieved, illustrating the good adaptability of the bubble detection system in various complex environments. The proposed self-powered wireless bubble detection strategy shows promising potential applications in boiling two-phase system, chemical engineering industry, and biomedical system. © 2025 Elsevier Ltd.