Futuristic Fabrics: Liquid Metal Leap Redefines Wearable Tech

What comes to mind when you imagine wearable technology of the future? Whatever your vision is, chances are the technology is sleek and integrated into fashion. Today’s wearables, like watches, rings, or glasses, often fail to live up to these futuristic standards due to their bulky, hard structures. The reason for this clunky form factor is deeply tied with nearly every electronic device: the printed circuit board. Now, imagine if technology wasn’t bound to this decades-old technology. What if circuit boards could bend?

What used to look like science fiction is quickly becoming a reality, amidst the rapidly advancing field of deformable circuits. The Virginia Tech Soft Materials and Structures lab is pioneering a unique manufacturing process for flexible circuit boards that allows components to be seamlessly integrated into fabrics.

Picture a circuit board: green, hard, and flat. How do you make that bendable? The key is the use of different metals and a base material tailored for the needs of a soft circuit. Traditionally, printed circuit boards are rigid fiberglass with copper wiring. These new soft circuits, however, replace the copper with a liquid metal, specifically the alloy eutectic gallium-indium, which remains fluid at room temperature. This difference is the fundamental principle behind soft circuits. This flexible, liquid “wiring” is the key to creating a circuit that can be twisted, folded, and layered. Instead of a fiberglass base, the liquid metal is encapsulated in a rubbery polymer, specifically styrene–isoprene–styrene, which can be bonded to fabrics.

The key innovation from the brilliant minds in the VT Soft Materials and Structures Lab lies not in inventing the concept of a soft circuit, nor circuits integrated into textiles, but in developing a manufacturing process that uniquely blends the two existing concepts, enhancing them by adding waterproof properties, improved deformability, and robust multi-layered circuit capabilities.

This new manufacturing process essentially encases the liquid metal into a stretchy material, surrounded by a textile, like cotton or spandex. To begin, a sheet of rubbery material is bonded to the fabric base. Then, a stencil is used to spray the liquid metal into place. All rigid electronic components are then placed in their pre-determined spaces. Layers are added in a similar manner. Once all the circuitry is complete, another sheet of rubbery material is bonded to the top of this, along with another sheet of textile. The complete encapsulation of the liquid metal in this rubbery elastomer allows the entire textile to stretch past 300% of its length without losing electrical continuity, survive hundreds of folds, and continue to function underwater.

What can we do with circuits that are as flexible as we are? The possibilities are endless. There are, of course, applications like fitness tracking devices in the form of headbands, bracelets, and potentially even shirts or socks. Another significant area is medical devices, where comfortable, body-conforming sensors could monitor vital signs, aid in physical therapy, or deliver medication.

The age of clunky and bulky wearable technology is coming to an end, and will eventually be replaced by sleek, flexibly integrated electronics that enhance our capabilities without hindering our natural movements. The Virginia Tech Soft Materials and Structures Lab has undeniably pushed the boundaries of what is possible, setting the stage for a revolution in how we conceive and interact with electronic devices in our daily lives.