20 research outputs found
The influence of surface energetic heterogeneity on electrofluidic gating of a metal oxide surfaces
An Integrated Microfluidic Chip System for Single-Cell Secretion Profiling of Rare Circulating Tumor Cells
Quantitating CellâCell Interaction Functions with Applications to Glioblastoma Multiforme Cancer Cells
Adsorption-induced slip inhibition for polymer melts on ideal substrates
Hydrodynamic slip, the motion of a liquid along a solid surface, represents a fundamental phenomenon in fluid dynamics that governs liquid transport at small scales. For polymeric liquids, de Gennes predicted that the Navier boundary condition together with polymer reptation implies extraordinarily large interfacial slip for entangled polymer melts on ideal surfaces; this Navier-de Gennes model was confirmed using dewetting experiments on ultrasmooth, low-energy substrates. Here, we use capillary levelingâsurface tension driven flow of films with initially non-uniform thicknessâof polymeric films on these same substrates.Measurement of the slip length from a robust one parameter fit to a lubrication model is achieved. We show that at the low shear rates involved in leveling experiments as compared to dewetting ones, the employed substrates can no longer be considered ideal. The data is instead consistent with a model that includes physical adsorption of polymer chains at the solid/liquid interface.Paris Sciences et Lettre