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Self-Catalyzed Chemically Coalescing Liquid Metal Emulsions
Stephanie F Zopf1, Ramón E Sánchez Cruz1, Chloe Kekedjian2
1Department of Mechanical Engineering, Boston University, 730 Commonwealth Avenue, Boston, MA, 02215, USA.
Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
|April 26, 2025
Summary
Researchers developed a new method to improve the electrical conductivity of liquid metal emulsions (LMEs) using chemical activation with halide compounds. This process enables facile 3D printing of functional electronic devices at mild temperatures.
Area of Science:
- Materials Science
- Nanotechnology
- Chemical Engineering
Background:
- Gallium-based liquid metal alloys (GaLMAs) are versatile materials for soft electronics and energy devices.
- Liquid metal emulsions (LMEs) offer improved processability but suffer from reduced electrical conductivity due to surface oxides.
- Current methods to restore conductivity require harsh conditions, limiting applications.
Purpose of the Study:
- To develop a mild, chemical method for coalescing liquid metal droplets in LMEs.
- To create 3D printable LME inks with high electrical conductivity and shape retention.
- To demonstrate the fabrication of functional electronic devices using these inks.
Main Methods:
- Incorporation of halide compounds into eutectic gallium indium (eGaIn) liquid metal emulsions.
- Chemical etching of oxide layers on dispersed droplets at mild temperatures (∼80 °C).
- Optimization of ink formulations for direct ink writing (DIW) by varying halide type, concentration, and mixing conditions.
Main Results:
- Achieved electrical conductivity close to bulk liquid metal (2.4 × 104 S cm-1) after chemical activation and heating.
- Developed 3D printable LME inks with excellent shape retention and DIW compatibility.
- Successfully fabricated a battery-integrated light-emitting diode array using a hybrid 3D printing process.
Conclusions:
- Chemical activation with halide compounds provides an effective route to restore conductivity in LMEs at mild temperatures.
- The developed LME inks are suitable for additive manufacturing of complex electronic devices.
- This approach enables nondestructive, low-temperature activation for functional device fabrication.
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