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Researchers from Korea Advanced Institute of Science and Technology (KAIST), Sookmyung Women’s University, and Aldaver have developed a flexible electronic textile platform that prints sensors directly onto fabric using Direct Ink Writing (DIW).
Published in npj Flexible Electronics, the work introduces a more adaptable and scalable method for creating smart garments that monitor human movement and physiology in real time.
Unlike traditional e-textile methods that rely on yarn coating or stencil-based printing, DIW allows for customized patterns on both sides of the fabric, including multilayered structures. This means that circuits, sensors, and interconnects can all be embedded into wearable items without affecting flexibility or comfort.
Tested for combat readiness
To create this platform, the researchers formulated three distinct inks. The first, designed for strain sensing, combines styrene-butadiene-styrene (SBS) with multi-walled carbon nanotubes to form a stretchable, conductive material. This ink enabled the production of sensors that remained functional through 10,000 cycles at 30% strain, achieving a gauge factor of 11.07 and showing consistent performance under washing, friction, and pressure.
The second ink, used for interconnects, contains silver flakes mixed with polystyrene. By adjusting the ink’s viscosity, the team controlled how deeply it penetrated the fabric, allowing the creation of via holes that connect different textile layers. These printed interconnects preserved low resistance values between 0.2 and 0.4 Ω and remained stable under mechanical stress. The ability to selectively form connections across layers is central to building complex, multilayered circuits within soft garments.
A third ink serves as a passive temperature indicator. Using leuco dye, it changes color in response to heat, providing a visual cue within a range of 0°C to 90°C. This ink does not require electrodes or power sources and can be printed in any shape, offering a lightweight solution for environmental or body temperature sensing.
The team demonstrated the platform’s capabilities through several practical tests. Sensors were printed on garments at the shoulder, elbow, and knee to monitor motion during common exercises such as running, jumping jacks, and push-ups. Each joint showed distinct patterns of resistance change, enabling accurate detection of posture and activity. The sensors also performed reliably under exposure to sweat and maintained accuracy after machine washing.
In another test, the researchers printed strain sensors onto a cotton face mask to track breathing. During exercise, breathing intensity and frequency increased, and the sensors registered these changes clearly. The system remained unresponsive to airflow from external sources such as wind, confirming its selective response to respiration.
To explore more advanced applications, the researchers created a glove equipped with strain sensors along the joints and pressure sensors at the fingertips. The glove was trained to recognize six different objects through grasping patterns and achieved over 96% classification accuracy using machine learning models. A second glove incorporated a multilayer design that allowed simultaneous detection of strain and pressure at a single point, without compromising flexibility.
While the technology is broadly applicable, it was developed with military use in mind. Traditional combat training often applies uniform routines regardless of an individual’s capabilities or role. By embedding sensors into standard military clothing, the new platform enables detailed tracking of motion and physical exertion, allowing training programs to be tailored to each soldier.
Major Kyusoon Pak of the South Korean Army, who participated in the research, emphasized that the platform was designed for both military relevance and large-scale implementation. With its robustness, affordability, and compatibility with standard combat uniforms, the technology is suited for deployment across a wide range of operational contexts.
He added, “I hope this research will be evaluated as a case that achieved both scientific contribution and military applicability.”
Wearables evolve beyond concept stage
From military uniforms to runway fashion, e-textiles are entering everyday life with real-world use cases.
At Boston Fashion Week 2024, MIT-based fashion designer Ganit Goldstein presented the “Electric Skin” collection, featuring four garments embedded with sensors and conductive materials. The textiles responded to environmental stimuli such as touch and proximity by changing color and texture, demonstrating adaptive interactivity.
Hosted at The Foundry as part of the Cambridge Science Festival, the showcase also included a VR application that used motion tracking to convert recorded body movements into an interactive dance performance. The work highlighted the technical potential of integrating sensor systems into textiles for responsive, immersive experiences.
Google’s Advanced Technology and Projects (ATAP) division harnessed Stratasys’ PolyJet 3D printing technology to streamline the development of its Jacquard wearable sensors, which enable gesture-based control in everyday clothing. Using the Stratasys J8 system, the team significantly reduced prototyping time from three weeks to just one day, while replicating material textures through the printer’s Pantone Matching System.
These compact, motion-sensitive tags were integrated into products such as smart backpacks and gaming shoes. The process enabled faster design iteration and helped ATAP fine-tune how sensors could be discreetly embedded into fashion items without compromising aesthetics or functionality.
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Featured image shows overview of the Direct Ink Writing (DIW) printed textile electronics. Image via KAIST.
