Solution processable liquid metal nanodroplets by surface-initiated atom transfer radical polymerization.

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Chemistry

Background:

• Eutectic gallium indium (EGaIn) is a room-temperature liquid metal alloy.
• EGaIn microdroplets in elastomers create stretchable, conductive composites for soft robotics and self-healing electronics.
• Current preparation methods yield irregular droplets and anisotropic properties.

Purpose of the Study:

• To develop a method for synthesizing stable sub-micrometre-sized EGaIn nanodroplets.
• To compatibilize EGaIn nanodroplets within polymer matrices and solvents.
• To enable solution-casting of flexible hybrid materials incorporating EGaIn nanodroplets.

Main Methods:

• Surface-initiated atom transfer radical polymerization was used to covalently functionalize the EGaIn nanodroplet surface with polymers.
• Polymers used include PMMA, PBMA, PDMAEMA, and PBA-b-PMMA.
• Nanodroplets were dispersed in solvents and polymer matrices up to 50 wt% concentration.

Main Results:

• Stable EGaIn nanodroplets were synthesized via polymeric ligand encapsulation.
• Nanodroplets demonstrated stability in organic solvents, water, and polymer matrices.
• The resulting hybrid materials exhibited good mechanical, thermal, and optical properties.
• Crystallization and melting temperatures were significantly suppressed (down to -80°C).

Conclusions:

• Polymeric ligand encapsulation provides a robust method for creating stable EGaIn nanodroplets.
• These stabilized nanodroplets are suitable for solution-casting into advanced flexible hybrid materials.
• The enhanced thermal stability and processability of EGaIn nanodroplets open new avenues in soft electronics and robotics.