Long range signature of liquid's inertia in nanoscale drainage flows

• Published in: Soft matter 2024-11, Vol.2 (44), p.884-8811
• Main Authors: Bigan, Nathan, Lizée, Mathieu, Pascual, Marc, Niguès, Antoine, Bocquet, Lydéric, Siria, Alessandro
• Format: Article
• Language: English
• Subjects: Deformation effects; Elastic deformation; Fluid dynamics; Hydrodynamics; Liquid flow; Microfluidics; Nanotechnology; Parameter identification; Physics; Solid surfaces; Surface force apparatus
• ISSN: 1744-683X; 1744-6848; 1744-6848
• DOI: 10.1039/d4sm01006j

In confinement, liquid flows are governed by a complex interplay of molecular, viscous and elastic forces. When a fluid is confined between two approaching surfaces, a transition is generally observed from a long range dynamical response dominated by viscous forces in the fluid to a short range elasto-hydrodynamic response due to the elastic deformation of the solid materials. This study investigates the behavior of fluids driven between oscillating solid surfaces using a dynamic Surface Force Apparatus. Our findings reveal that the dominant influence on fluid behavior arises from long-range inertial effects, superseding conventional elasto-hydrodynamic effects. Through systematic experimentation involving fluids of varied viscosities, diverse substrates, we identify key parameters and develop a comprehensive model which explains our measurements. Our findings not only provide insights into confined fluid dynamics but also offer practical implications for various applications in microfluidics, nanotechnology and liquid lubrication. In confinement, liquid flows are governed by a complex interplay of molecular, viscous and elastic forces.