Interfacial slip modulated by water structure at negatively charged surface

Abstract

The mechanism of interfacial slip is of great importance in many applications. In this work, interfacial slip length is calculate based on the atomic force microscopy measurement in different solutions on different surfaces. Results show that solutions of higher concentration, cations of stronger hydration capacity and surfaces with higher hydrophobicity would promote slip. Besides, we use sum frequency generation vibrational spectroscopy to directly identify the interfacial water structures. These results indicate cations and surface characteristics would strongly affect interfacial water structures, suggesting the less amount of interfacial water and higher proportion of disordered water would increase slip length. This work may provide some insights to the relationship between interfacial slip and interfacial structures from the perspective of water structures.