Plasmonic Imaging of Spatiotemporal Electrochemical Bubble Evolution on Smooth Electrodes with Different Wettabilities

Although evolution dynamic investigation onto electrochemically generated bubbles on electrode surfaces is crucial for releasing "bubble blocking" effects, traditional "top view" or "side view" methods make spatiotemporal interfacial revolutions difficult to achieve, which are critical for a deeper understanding and better electrode design. In this study, a novel method utilizing surface plasmon resonance (SPR) is proposed to probe bubble interfacial dynamics. By monitoring reflectivity changes and utilizing differential imaging, real-time fluctuations in the contact area can be accurately visualized. The investigation onto bubble growth events on both aerophilic and aerophobic surfaces reveals that they occur in very distinct patterns. Due to the "necking effect", the reflectivity of aerophilic electrodes rushed to its highest value and remained or gradually decreased, followed by a sudden drop due to bubble disengagement. While the aerophobic ones increased to the bubble release threshold after a downward parabola function, then dropped abruptly without plateau. This in situ imaging technique provides a feasible tool for bubble disengagement dynamic investigations on electrode surface. Based on current observations, it is revealed that changing the wettability of electrodes causes substantial changes in bubble evolution dynamics.