MXene-Coated Liquid Metal Nanodroplet Aggregates.

Area of Science:

• Materials Science
• Nanotechnology
• Soft Matter Physics

Background:

• Liquid metal (LM) and nanomaterial composites offer synergistic properties but suffer from uniform dispersion and high LM volume fractions.
• Existing composites require >60 vol % LM, leading to leakage issues in thermal management and wearable electronics.
• Lack of self-assembly or aggregation in current LM composites limits their performance and applicability.

Purpose of the Study:

• To engineer soft LM composites with self-assembling capabilities.
• To enhance thermal and electrical conductivity using significantly lower LM volume fractions.
• To mitigate LM leakage and improve material stability for practical applications.

Main Methods:

• Coating nanoscale eutectic gallium-indium (EGaIn) LM droplets with Ti₃C₂T MXene sheets (0.25 vol %).
• Creating 'sticky' LM particles that self-assemble into semisolid aggregates within a silicone oil matrix.
• Investigating the impact of aggregation and interfacial thickness on composite properties.

Main Results:

• Achieved self-assembly of MXene-coated EGaIn droplets into aggregates, altering composite morphology.
• Demonstrated an exponential increase in thermal and electrical conductivity with decreasing interfacial thickness.
• Enabled high conductivity at significantly reduced LM volume fractions (25 vol %) without LM rupture or bleed-out.

Conclusions:

• Introducing aggregation as a design parameter in soft LM composites dramatically alters thermal and electrical resistance.
• MXene-LM-silicone composites offer superior performance compared to those with individual components.
• This approach enables more effective thermal interface materials (TIMs) and printed electronics with reduced filler material.