Slip effects in polymer thin films

TL;DR

This paper reviews how slip effects influence the flow dynamics of polymer thin films, using dewetting as a tool to understand solid/liquid boundary conditions and molecular-scale slippage.

Contribution

It provides a comprehensive overview of models, experimental results, and molecular explanations for slip effects in polymer thin films.

Findings

Dewetting reveals boundary conditions at the solid/liquid interface.

Viscous dissipation and slippage balance interfacial forces.

Molecular-scale concepts help explain slippage phenomena.

Abstract

Probing the fluid dynamics of thin films is an excellent tool to study the solid/liquid boundary condition. There is no need for external stimulation or pumping of the liquid due to the fact that the dewetting process, an internal mechanism, acts as a driving force for liquid flow. Viscous dissipation within the liquid and slippage balance interfacial forces. Thereby, friction at the solid/liquid interface plays a key role towards the flow dynamics of the liquid. Probing the temporal and spatial evolution of growing holes or retracting straight fronts gives, in combination with theoretical models, information of the liquid flow field and especially the boundary condition at the interface. We review the basic models and experimental results obtained during the last years with exclusive regard to polymers as ideal model liquids for fluid flow. Moreover, concepts that aim on explaining slippage on the molecular scale are summarized and discussed.