Low Temperature Nano-Soldering on Electroplated Textiles for Wearable Electronics

Electronic textile applications such as wearable health monitors, sensors, and smart clothing are experiencing rapid development, highlighting the need for robust textile integrated electronics. However, progress is limited by the instability of conventional metallization and bonding approaches. Sputter coating or other thin-film processing methods, commonly used to create conductive pathways on fabrics, exhibit limited mechanical anchoring and penetration to textile fibers, making them susceptible to cracking, delamination, and loss of conductivity under deformation or washing. Furthermore, the porous and fibrous structure of fabrics poses additional challenges for electronics development and integration, compared to traditional rigid substrates. These constraints highlight the need for effective joining strategies that provide both mechanical robustness and electrically reliable interfaces at temperatures compatible with fabric substrates. This work addresses these limitations by applying electroplated coatings to cotton-based fabrics. Electroplating produces a conformal, micron‑scale metallic layer that penetrates the textile weave, offering significantly improved coverage and mechanical anchoring compared to the sputtered films.

Unlike traditional solders such as SAC alloys, which require high reflow temperatures (220-250 °C), far exceeding what cotton-based textiles can withstand, nano-solders allow for bonding at significantly lower temperatures that are compatible with fabric substrates. This study focuses on characterizing the cross‑sectional interface between several types of electroplated metals and nano-solders, examining their wetting behavior, intermetallic formation, and joint morphology across fiber surfaces. Preliminary results indicate continuous solder wetting on plated fibers, enhanced joint uniformity, and improved electrical stability under mechanical deformation. The combined electroplating and nano-soldering approach establishes a pathway in forming mechanically robust and electrically reliable interconnects for next-generation E-textiles. Ongoing work quantifies long‑term durability, assessing soldering capability and joining of electronic components onto electroplated fabric substrates to achieve device assembly and integration.