Multi-material direct ink writing and embroidery for stretchable wearable sensors

Conference item

The development of wearable sensing systems for sports performance tracking, rehabilitation, and injury prevention has driven a growing demand for smart garments that combine comfort, durability, and accurate motion detection. This paper presents a textile-compatible fabrication workflow that integrates multi-material direct ink writing with automated embroidery to create stretchable strain sensors directly embedded onto garments. The process combines sequential multi-material printing of a silicone–carbon grease–silicone stack with automated embroidery, which provides both mechanical fixation and electrical interfacing in a single step. The resulting hybrid sensor demonstrates stretchability up to 120% strain while maintaining electrical continuity, with approximately linear behaviour up to 60% strain (R² = 0.99), a gauge factor of 31.4, and a hysteresis of 22.9%. Repeated loading–unloading tests over 80 cycles show baseline and peak drift of 0.135% and 0.236% per cycle, respectively, reflecting moderate cycle-to-cycle stability. Mechanical testing further confirms that the silicone–fabric interface remains intact under large deformation, with failure occurring in the textile rather than at the stitched boundary. As a preliminary proof of concept, the sensor was integrated into wearable elbow and knee sleeves for joint angle monitoring, showing a clear correlation between normalised resistance change (ΔR/R) and bending angle. By addressing both mechanical fixation and electrical interfacing through embroidery-based integration, this approach provides a reproducible and scalable pathway for incorporating printed stretchable electronics into textile systems for motion capture and soft robotic applications.

Authors: Cha, L; Hashem, R; Prakash, R; Declety, T; Zhang, W

• Publication status: Accepted
• Peer review status: Peer reviewed
• Publisher: IEEE
• Publication date: 2026-03-18
• Acceptance date: 2026-01-30
• Event title: 9th IEEE-RAS International Conference on Soft Robotics (RoboSoft 2026)
• Event location: Kanazawa, Japan
• Event website: https://www.robosoft2026.org/
• Event start date: 2026-04-07
• Event end date: 2026-04-11
• Language: English
• Keywords: soft sensors; fabrication; textiles; wearables