Conductive Fabrics for Textile Electronic Interconnections and Capacitive Sensing - A Smart Textiles Perspective

Licentiate thesis, 2017

Smart textiles offer ways to integrate sensing and actuating abilities into textile structures found in garments, furniture and other applications such as filters, reinforcements, disposable products and others. A large part of the research being done on smart textiles concerns the possibilities for monitoring human health and wellbeing. In recent years, the research community has shown an increasing interest in measuring pressure using smart textiles. Observations in previous work on electrically conductive fabrics had shown that the conductivity in these fabrics was not always isotropic and the assumption was that the contact resistance between the conductive elements (often yarns) was the source of this anisotropy. The work done in connection to this thesis investigates two questions regarding smart textiles: first electrical interconnections and second electrical sensing. An algorithm and a device for measuring the contact resistance in woven samples were developed. Results from that work showed that the contact resistance of woven samples can be measured and that in the case of metallized yarns the contact resistance does not pose a problem for interconnection. For the sensing part two explanatory models for the capacitance of a functionalized spacer-fabric under compression were developed and tested on measured data. The results indicate that both models provide reasonable agreement with the data up to ca 50% compression.