2024/02/05 by Shuangshuang Meng, Meng, Shuangshuang, Yu Han +17
Engineering · #Electrohydrodynamics and Fluid Dynamics #FOS: Physical sciences #Instrumentation and Detectors (physics.ins-det) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Microfluidic and Bio-sensing Technologies #Optics (physics.optics)
paper · pdf · doi:10.48550/arxiv.2402.04279
openalex publication_date 2024/02/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The zeta (ζ) potential is a pivotal metric for characterizing the electric field topology within an electric double layer - an important phenomenon on phase interface. It underpins critical processes in diverse realms such as chemistry, biomedical engineering, and micro/nanofluidics. Yet, local measurement of ζ potential at the interface has historically presented challenges, leading researchers to simplify a chemically homogenized surface with a uniform ζ potential. In the current investigation, we present evidence that, within a microchannel, the spatial distribution of ζ potential across a chemically homogeneous solid-liquid interface can become two-dimensional (2D) under an imposed flow regime, as disclosed by a state-of-art fluorescence photobleaching electrochemistry analyzer (FLEA) technique. The ζ potential' s propensity to become increasingly negative downstream, presents an approximately symmetric, V-shaped pattern in the spanwise orientation. Intriguingly, and of notable significance to chemistry and engineering, this 2D ζ potential framework was found to electrokinetically induce swirling flows in tens of nanometers, aligning with the streamwise axis, bearing a remarkable resemblance to the well-documented hairpin vortices in turbulent boundary layers. Our findings gesture towards a novel perspective on the genesis of vortex structures in nanoscale. Additionally, the FLEA technique emerges as a potent tool for discerning ζ potential at a local scale with high resolution, potentially accelerating the evolution and applications of novel surface material.