Wall slip for complex liquids - Phenomenon and its causes

Area of Science:

• Rheology and Fluid Dynamics
• Materials Science

Background:

• Wall slip is a complex phenomenon affecting fluid flow near solid interfaces.
• Existing literature offers diverse perspectives on the mechanisms driving wall slip.

Purpose of the Study:

• To comprehensively review and categorize the types and mechanisms of wall slip.
• To highlight recent advancements and persistent challenges in understanding wall slip.
• To cover a broad spectrum of fluids, including liquids, solutions, dispersions, and melts.

Main Methods:

• Review of theoretical, numerical, and experimental studies on wall slip.
• Analysis of fluid-solid wall interactions and shear-induced transitions.
• Examination of factors like wetting properties, nanobubbles, microcavities, and surface topography.

Main Results:

• Identified two primary mechanisms: fluid-solid wall interaction and shear-induced fluid-to-solid transitions.
• Discussed the role of wetting, nanobubbles, and microcavities in slip phenomena.
• Analyzed slip in multi-component systems, including viscoplastic media and concentrated dispersions undergoing strain-induced glass transitions.
• Highlighted liquid-to-solid transitions as a key mechanism in polymer melts.

Conclusions:

• Wall slip is governed by fundamental interactions at the fluid-solid interface and shear-induced state transitions.
• Surface characteristics and fluid properties significantly influence slip behavior.
• Further research is needed to fully elucidate slip mechanisms across diverse fluid systems.