Translucency and temperature dependence for the slip length of water on graphene Han Li and Ming Ma Tsinghua University, China Carbonous materials, such as graphene and carbon nanotube, have attracted tremendous attention in the fields of nanofluidics due to the slip at the interface between solid and liquid. The dependence of slip length for water on the types of supporting substrates and thickness of carbonous layer, which is critical for applications such as sustainable cooling of electronic devices, remains unknown. In this paper, using colloidal probe atomic force microscope, we measured the slip length of water on graphene l s supported by hydrophilic and hydrophobic substrates, i.e. , SiO 2 and octadecyltrimethoxysilane (OTS). With the thickness of few-layer graphene increases to 3~4 layers, both l s gradually converge to the value of graphite. Such thickness dependence is termed slip length translucency. Further, l s is found to decrease by about 70% with the temperature increases from 300 K to 350 K for 2-layer graphene supported by SiO 2 . These observations are explained by analysis based on Green-Kubo relation and McLachlan theory. Our results provide the first set of reference values for the slip length of water on supported few-layer graphene. They can not only serve as a direct experimental reference for solid-liquid interaction, but also provide guideline for the design of nanofluidics-based devices, for example the thermo- mechanical nanofluidic devices. References 1. Han Li, Z. X., Chen Ma, Ming Ma, Translucency and negative temperaturedependence for the slip length of water on graphene. Nanoscale 2022.
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