Researchers at Virginia Tech have uncovered how tiny droplets of liquid metal can connect to form electrical pathways inside soft materials. The discovery could help advance flexible electronics, wearable sensors and soft robotic devices.

The research explains a mechanism that scientists have been trying to understand for years: how electricity travels between separate liquid metal droplets surrounded by insulating materials.

How Does the New Technology Work?

The research team, led by mechanical engineering professor Michael Bartlett, studied a liquid metal alloy known as eutectic gallium-indium (EGaIn). This alloy remains liquid at room temperature and can be incorporated into flexible materials such as rubber and polymers.

Inside these materials, the liquid metal exists as numerous microscopic droplets. Although the droplets can conduct electricity, the surrounding polymer or rubber normally prevents them from connecting directly.

Scientists discovered that applying mechanical pressure creates tiny cracks in the insulating material between nearby droplets. Liquid metal then flows into these cracks and creates connected pathways through which electrical current can travel.

Interestingly, some of the liquid metal remains inside these pathways even after the pressure is released, allowing the material to retain its electrical conductivity.

Advanced Imaging Reveals the Electrical Connection

To understand the process, researchers used microscopy and three-dimensional X-ray imaging to observe how liquid metal behaves when soft materials are compressed.

These observations helped the team reconstruct the electrical pathways in three dimensions and understand how microscopic cracks develop into larger conductive networks.

The researchers also developed a mathematical model that can predict how much mechanical force is required to activate electrical conductivity.

The model worked across different material designs, including structures containing droplets ranging from millimetre-scale sizes to just a few dozen micrometres.

Potential Applications in Future Electronics

The discovery could provide engineers with greater control over the development of flexible electronic systems.

Some potential applications include:

• Wearable electronics: Flexible devices that can maintain electrical connections while bending and stretching.
• Smart sensors: Stretchable sensors capable of responding to pressure and movement.
• Soft robotics: Robotic systems that require flexible electronic circuits to move and change shape.
• Flexible circuits: Electrical pathways that can be activated through controlled mechanical pressure.
• Advanced materials: Soft materials with conductivity that can be designed for specific applications.

The research may also help manufacturers develop electronic components in which electrical connections form at predetermined locations and under specific mechanical conditions.

Why Is This Research Important?

Traditional electronic circuits generally depend on rigid conductive materials and carefully manufactured connections. These approaches can become challenging when devices need to stretch, bend or change shape.

Liquid metal composites offer another approach because they combine the electrical conductivity of metals with the flexibility of soft materials.

However, controlling exactly when and where these materials become electrically conductive has remained a significant engineering challenge.

By identifying the role of microscopic cracks, Virginia Tech researchers have provided a scientific explanation that could make the design and manufacturing of soft electronic materials more predictable.

Research Published in the Journal Matter

The research was conducted by Michael Bartlett and doctoral researchers Wuzhou Zu and Hugh P. Grennan at Virginia Tech.

The findings were published in the scientific journal Matter on October 29, 2026.

Research paper: Fracture-Mediated Percolation Governs Electrical Activation in Liquid Metal Composite Conductors.

DOI: 10.1016/j.matt.2026.103089

Conclusion

The discovery of how microscopic cracks connect liquid metal droplets offers a new direction for flexible electronics research. By understanding how pressure creates conductive pathways, scientists can work towards designing more controllable stretchable sensors, wearable devices and soft robotic systems.

Although commercial applications will require further engineering and testing, the findings provide an important foundation for developing the next generation of flexible electronic materials.