Fast and versatile thermo-osmotic flows with a pinch of salt. Issue 3 (6th January 2022)

• Record Type: Journal Article
• Authors: Herrero, Cecilia; De San Féliciano, Michael; Merabia, Samy; Joly, Laurent
• Is Part Of: Nanoscale. Volume 14:Issue 3(2022)
• Page Start: 626
• Page End: 631
• Publication Date: 2022-01-06
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d1nr06998e
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Fast and versatile thermally induced flows can be obtained on slipping charged surfaces with applications for waste heat harvesting. Abstract : Thermo-osmotic flows – flows generated in micro and nanofluidic systems by thermal gradients – could provide an alternative approach to harvest waste heat. However, such use would require massive thermo-osmotic flows, which are up to now only predicted for special and expensive materials. Thus, there is an urgent need to design affordable nanofluidic systems displaying large thermo-osmotic coefficients. In this paper, we propose a general model for thermo-osmosis of aqueous electrolytes in charged nanofluidic channels, taking into account hydrodynamic slip, together with the different solvent and solute contributions to the thermo-osmotic response. We apply this model to a wide range of systems by studying the effects of wetting, salt type and concentration, and surface charge. We show that intense thermo-osmotic flows can be generated using slipping charged surfaces. We also predict for intermediate wettings a transition from a thermophobic to a thermophilic behavior depending on the surface charge and salt concentration. Overall, this theoretical framework opens an avenue for controlling and manipulating thermally induced flows with common charged surfaces and a pinch of salt.