New Electrochemical Approach for Assessing Surface Tension and its Role in Atmospheric Particle Growth

Despite numerous studies addressing the complex role of surface-active substances (SAS) in cloud condensation nuclei, a significant gap exists in understanding their intrinsic importance and involvement, particularly in gas uptake and atmospheric particle growth. In this study, we advance the application of electrochemistry in this field and provide new insights into the role and impact of hydrophilic/hydrophobic SAS on the growth of atmospheric aerosol particles. We employed an innovative approach based on non-faradaic electrochemistry. A change of the measured capacitive current (dI_capacity) is caused by the adsorption of SAS on the electrode surface, which is directly proportional to the change of surface tension (dγ). The application of this new methodology, combined initially with the mercury electrode, demonstrated significantly higher sensitivity and reliability compared to other conventional tensiometric methods for measuring surface tension. Moreover, the effectiveness of this strategy was tested and validated using the environmentally friendly bismuth electrode as an excellent alternative.