Temperature-dependent slip length for water and electrolyte solution

Hypothesis: The temperature dependence of boundary slip at liquid-solid interface is critical both for the fundamental theory and applications of fluid mechanics on micro and nanoscale, such as sustainable cooling of electronic devices. However, there is a controversy on the temperature dependence of bound-ary slip which lacks experimental evidence, we aim to resolve it by hypothesizing that the temperature dependent slip length depends on the variation in the interfacial energy barrier.Experiments: Here, we measured ls - T relation of water and NaCl solution on self-assembled FDTS (Perfluorodecyltrichlorosilane) surface using colloidal probe AFM. The transition of ls - T monotonicity is found. For water and 0.1 M NaCl solution, ls is negatively correlated with T, while for 1 M NaCl solution, ls is positively correlated with T.Findings: Together with molecular dynamics simulations, such observation is quantitatively explained with an analytical model based on rate theory, where the ls - T monotonicity depends on the difference between liquid-solid interfacial energy barrier and liquid internal energy barrier. Our results provide not only solid experimental evidence for the boundary slip being a rate process, but also a basis for the thermal-hydrodynamic design of microfluidic and nanofluidic devices.(c) 2023 Elsevier Inc. All rights reserved.

Automated summary

This study provides experimental evidence for the temperature dependence of boundary slip at the liquid-solid interface. The results show that the slip length is negatively correlated with temperature for water and 0.1 M NaCl solution, but positively correlated with temperature for 1 M NaCl solution.