High-speed imaging of CNT deagglomeration in aqueous solution with surfactant

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Effective dispersion of multi-walled carbon nanotubes (MWCNTs) is crucial for their applications.
• Ultrasonication is a common method for MWCNT dispersion, but its efficiency can be limited.
• Surfactants are often used to improve MWCNT dispersion, but their precise role in deagglomeration mechanisms is not fully understood.

Purpose of the Study:

• To investigate the mesoscale deagglomeration mechanisms of MWCNTs in aqueous solutions.
• To elucidate the role of surfactant (Triton X-100) in MWCNT deagglomeration during ultrasonication.
• To understand the influence of cavitation zones and microbubble dynamics on MWCNT dispersion.

Main Methods:

• High-speed imaging was employed to observe MWCNT deagglomeration in real-time.
• Numerical simulations were conducted to model bubble dynamics and their interaction with MWCNT agglomerates.
• Experiments were performed in aqueous solutions with and without Triton X-100 surfactant.

Main Results:

• Within the cavitation zone (CZ), surfactant addition showed minimal effect on MWCNT deagglomeration.
• Outside the CZ, surfactant significantly increased microbubble cluster formation and stability.
• Surfactant-facilitated microbubble interactions led to more frequent MWCNT deagglomeration in regions away from the sonotrode.

Conclusions:

• Surfactants enhance MWCNT dispersion by promoting microbubble-mediated deagglomeration outside the primary cavitation zone.
• Structured microbubble activity, influenced by surfactants, extends the effective dispersion region during ultrasonication.
• These findings offer insights for optimizing MWCNT processing in surfactant-assisted systems.