Mahmoud Tavakoli | University of Coimbra: What are the key components and advantages of liquid metal-based biphasic composite inks for stretchable electronics?

Can conductive circuit inks survive 1000% stretchable strain without losing electrical conductivity?

Conventional flexible electronics struggle with rigid, non-developable 3D surfaces and often fail under high mechanical stress. To overcome this limitation, a novel stretchable, self-healing, and sinter-free ink technology has been developed using liquid metal. This formulation combines metallic conductivity with fluidic behavior, enabling unprecedented mechanical performance.

By embedding liquid metal into the polymer binder, the circuits can survive extreme deformation. In tests on elastomeric substrates, these printed traces achieved over 1000% stretchability, with some reaching up to 2000% strain. This performance sets a new benchmark in the field of stretchable electronics.

Furthermore, this technology solves the critical challenge of microchip-to-substrate integration. While state-of-the-art methods rely on complex, high-temperature bonding steps, this liquid-metal approach allows surface-mount components to remain electrically connected even under 500% strain.

In this short video, you can learn:
* How liquid metal properties are leveraged to eliminate high-temperature sintering steps.
* The structural mechanics behind achieving a world-record 2000% strain in printed circuits.
* How microchips can be integrated into stretchable substrates to withstand high mechanical elongation.

📋 **Clip Abstract** This clip introduces a revolutionary liquid metal conductive ink that achieves up to 2000% stretchability without requiring high-temperature sintering. It demonstrates how embedding liquid metal allows microchips to remain functionally integrated under extreme physical deformation.

How does a biphasic ink formulation prevent printed trace degradation over 50,000 stretching cycles?

Standard silver or copper conductive inks suffer from severe degradation under cyclic strain. As these inks are stretched, micro-cracks form within the conductive network, permanently increasing resistance and leading to eventual circuit failure. This has historically limited the use of printed electronics in dynamic environments.

To solve this, a biphasic ink formulation has been designed that utilizes a liquid metal binder to actively weld conductive particles together. The fluidic phase remains highly integrated with the solid conductive phase during mechanical deformation, ensuring that the electrical pathway is never severed.

This mechanical stability allows the printed traces to maintain their original electrical conductivity over thousands of stretch cycles. Recent endurance testing demonstrated that these biphasic circuits can withstand over 50,000 cycles at 100% strain without noticeable resistance degradation.

In this short video, you can learn:
* Why conventional conductive inks fail under repeated mechanical stretching.
* The physics of a biphasic ink formulation using a liquid metal binder system.
* How to achieve stable conductivity over 50,000 cyclic strain runs at 100% elongation.

📋 **Clip Abstract** This segment details the degradation mechanism of conventional conductive inks under repeated strain and presents a biphasic alternative. By using a liquid metal binder that welds particles together, the ink survives 50,000 stretching cycles without loss of conductivity.

Is it possible to integrate active microchips onto flexible circuits without solder, epoxy, or heat?

Traditional surface-mount technology (SMT) relies on solder paste or conductive epoxies, which require elevated temperatures that damage heat-sensitive substrates. A new room-temperature assembly method bypasses thermal constraints entirely. By printing the liquid metal ink and placing the component, the integration is completed without any heat.

This bonding process relies on a physical process inside an activation chamber. This mechanical alignment enables reliable component attachment on low-cost polymers and bio-based textiles that cannot survive reflow soldering. The resulting joints are robust enough to withstand high strains.

Additionally, this unique liquid metal formulation allows damaged printed circuits to undergo self-healing. When a printed trace is physically sliced, placing the sample back into the activation chamber allows the fluidic metallic phases to reconnect and fully restore lost electrical conductivity.

In this short video, you can learn:
* How microchips are electrically integrated into polymer substrates at room temperature.
* The process of achieving durable electrical connections without solder or epoxies.
* How physical cuts in printed circuitry can self-heal to restore lost conductivity.

📋 **Clip Abstract** The video demonstrates a room-temperature method for integrating microchips onto flexible substrates without solder or epoxy. It also showcases the self-healing capability of liquid metal inks, which can restore electrical conductivity after deep physical cuts.