Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States.
Anal Chem. 2021 Mar 30;93(12):5170-5176. doi: 10.1021/acs.analchem.0c05067. Epub 2021 Mar 18.
Surfactants, mimics of contamination, play an important role in nanobubble nucleation, stability, and growth at the electrode surface. Herein, we utilize single-molecule fluorescence microscopy as a sensitive imaging tool to monitor nanobubble dynamics in the presence of a surfactant. Our results show that the presence of anionic and nonionic surfactants increase the rate of nanobubble nucleation at all potentials in a voltage scan. The fluorescence and electrochemical responses indicate the successful lowering of the critical gas concentration needed for nanobubble nucleation across all voltages. Furthermore, we demonstrate that the accumulation of surfactants at the gas-liquid interface changes the interaction of fluorophores with the nanobubble surface. Specifically, differences in fluorophore intensity and residence lifetime at the nanobubble surface suggest that the labeling of nanobubbles is affected by the nature of the nanobubble (size, shape, etc.) and the structure of the gas-liquid interface (surfactant charge, hydrophobicity, etc.).
表面活性剂作为污染物的模拟物，在纳米气泡的电极表面成核、稳定和生长中起着重要作用。在此，我们利用单分子荧光显微镜作为一种灵敏的成像工具来监测存在表面活性剂时的纳米气泡动力学。我们的结果表明，在电压扫描过程中，阴离子和非离子表面活性剂的存在增加了纳米气泡成核的速率。荧光和电化学响应表明，成功降低了在所有电压下纳米气泡成核所需的临界气体浓度。此外，我们证明了表面活性剂在气液界面的积累改变了荧光团与纳米气泡表面的相互作用。具体来说，荧光团在纳米气泡表面的强度和停留寿命的差异表明，纳米气泡的标记受纳米气泡的性质（大小、形状等）和气液界面的结构（表面活性剂电荷、疏水性等）的影响。
