A Shear Thickening Colloidal Suspension Functioning via Progressive Impact Jamming with Persistent Lubrication Layer.

Area of Science:

• Materials Science
• Fluid Dynamics
• Rheology

Background:

• Conventional shear thickening fluids (STFs) and their jamming dynamics are well-researched.
• Existing models explain hydrodynamics, lubrication breakdown, and interparticle friction in STFs.

Purpose of the Study:

• To investigate the jamming dynamics of ionic liquid-based shear thickening fluids (ILSTFs).
• To explore the lubricated nature of ILSTFs during shear thickening and impact-induced solidification.
• To develop a model for jamming dynamics in ILSTFs.

Main Methods:

• Rheology tests to characterize shear thickening behavior.
• Dynamic normal impact tests to trigger jamming and solidification.
• Development and application of a Modified Added Mass Model based on the Impact-Activated Normal Solidification (IANS) framework.

Main Results:

• ILSTFs exhibit lubricated behavior not only in strong shear thickening but also during jamming and solidification.
• A solvation layer of a few nanometers lubricates silica nanoparticles during impact jamming.
• The solvation layer thickness decreases due to squeezing from increasing stress, defining a progressive jamming realm.

Conclusions:

• Ionic liquid-based shear thickening fluids demonstrate unique lubricated jamming dynamics.
• The Modified Added Mass Model accurately describes jamming with a solid boundary.
• The findings introduce a new understanding of progressive jamming in ILSTFs.