Microstructural Dynamics and Rheology of Worm-like Diblock Copolymer Nanoparticle Dispersions under a Simple Shear...

Area of Science:

• Rheology
• Materials Science
• Nanotechnology

Background:

• Worm-like nanoparticles (WLNPs) exhibit unique flow properties.
• Understanding nanoparticle alignment under different flow conditions is crucial for material design.

Purpose of the Study:

• To investigate the shear and extensional flow behavior of two types of WLNPs with varying flexibility.
• To quantify the role of shear and extensional flows in aligning WLNPs.
• To explore the implications of WLNP alignment on rheological properties.

Main Methods:

• Utilized microfluidic devices to apply shear and planar extensional flows.
• Measured flow-induced birefringence (FIB) to quantify WLNP alignment.
• Analyzed rheological properties, including viscosity under different flow conditions.

Main Results:

• Both shear and extensional flows induce WLNP alignment.
• Extensional deformations are more effective than shear deformations in initiating WLNP alignment.
• WLNP dispersions exhibit shear-thinning and extensional-thinning behavior.
• Alignment is influenced by the solvent's Trouton ratio and WLNP structural parameters.

Conclusions:

• Extensional flows are superior to shear flows for aligning WLNPs.
• The observed rheological behavior (shear-thinning and extensional-thinning) makes WLNPs suitable for industrial and biotechnological applications involving extensional flows.