This work explores the feasibility of coupling two different techniques, the impedance and the transient plane source (TPS) principle, to quantify the moisture content and its compositional parameters simultaneously. The sensor is realized directly on textiles with the use of printing and coating technology. Impedance measurements use the fluid's electrical properties, while the TPS measurements are based on the thermal effusivity of the liquid. Impedance and TPS measurements show equal competency in measuring the fluid volume with a lowest measurable quantity of 0.5 μL, enabling ultralow volume passive measurements for sweat analysis. Both sensor principles were tested by monitoring the drying of a wet cloth and the measurements show perfect repeatability and accuracy. Nevertheless, when the biofluid property changes, the TPS sensor does not reflect this information on its readings, whereas, on the other hand, impedance can provide information on compositional changes. However, since the volume of the fluid changes simultaneously, one cannot differentiate between a volume change and a compositional change from impedance measurements alone. Therefore, we show in this work that we can apply impedance to measure the compositional properties; meanwhile, the TPS measurements accurately carry out volume measurements irrespective of the interferences from its compositional variations. To prove this, both of these techniques are applied for the quantification and composition monitoring of sweat, showing the capability to measure moisture content and compositional parameters simultaneously. TPS measurements can also be an indicator of the local temperature of the medium confined by the sensor, and it does not influence the fluid parameters. Compiling both impedance and thermal sensors in a single platform triggers smart wearable prospects of metering the liquid volume and simultaneously analyzing other compositional changes and body temperature. Finally, the repeatability and stability of the sensor readings and the washability of the device are tested. This device could be a potential sensing tool in real-life applications, such as wound monitoring and sweat analysis, and could be a promising addition toward future smart wearable sensors.

The smart textiles and wearable technology markets are expanding tirelessly, looking for efficient solutions to create long-lasting products. The research towards novel integration methods and increasing reliability of wearables and electronic textiles (e-textiles) is expanding. One obstacle to be tackled is the washability and the endurance to mechanical stresses in the washing machine. In this article, different layering of thermoplastic polyurethane (TPU) films and knit fabrics are used to integrate three different designs of stretchable copper-based meander tracks with printed circuit boards. The various combinations are washed according to the ISO 6330-2012 standard to analyze their endurance. Results suggest that one meander design withstands more washing cycles and indicate that the well-selected layer compositions increase the reliability. Higher stretchability together with greater durability is accomplished by adding an extra meander-shaped TPU film layer.

Research and development of new products in the smart textile field is growing rapidly because of versatile application areas. There is an extensive focus on the integration of electronics into textiles. However, if different fields are merged, as here, the sustainability and recycling issues might descend into even more complex systems. The paper reviews current research and development conducted on the end-of-life solutions for electronic textiles (e-textiles). Chosen papers had to be peer-reviewed, written in English, and address the end-of-life issue for electronic-based smart textiles. The search resulted in 18 publications, which indicates a low amount of research but also the serious lack of legislation and actual solutions emerged in this multidisciplinary field. Three main themes were found: smart textile services, eco-design strategy and educating guidelines. Authors suggest taking urgent actions by preventive steps in combining current electronics and textile waste management systems into one standard for e-textiles. TEXTILE INTEGRATED ELECTRONICS IN ECO-DESIGN CONTEXTVan Langenhove and Hertleer (2004) state "smart textiles are fabrics or apparel products that contain technologies, which sense and react to the conditions of the environment they are exposed to, thus allowing the wearer to experience increased functionality". The conditions or stimuli can be electrical, mechanical, thermal, chemical, or a combination of these. The main research in the smart textile field is indefinitely focused on improving the integration level, from moving from garment level to fibre level (Schneegass & Amft, 2017). For example, Katashev et al. (2019) replaced conventional EIT (electrical impedance tomography) electrodes with knitted textiles electrodes where conductive parts are on fibre level. Electronic textiles (e-textiles) are a subcategory of smart textiles that are based on electronics and conductive textiles, e.g. silver-coated fabrics or yarns, conductive inks and/or conductive polymers (Stoppa & Chiolerio, 2014). The E-textiles system includes the traditional electronic components, for example, printed circuit boards (PCB) and non-textile sensors that include ceramics in addition to metals and plastics.In e-textile products, the level of integration has a remarkable influence on the materials' recyclability and the end-of-life solutions of the product. As a result, e-textiles require specified end-of-life treatment methods and standardized waste processing. It is vital to tackle the topic early to avoid mistakes made in textile waste management. End of product lifetime or EOL (End-of-Life) of the product is the point when it is not usable anymore or just not needed by the user anymore. Thus, it should be reused, recycled, remanufactured or

Smart textiles have found numerous applications ranging from health monitoring to smart homes. Their main allure is their flexibility, which allows for seamless integration of sensing in everyday objects like clothing. The application domain also includes robotics; smart textiles have been used to improve human-robot interaction, to solve the problem of state estimation of soft robots, and for state estimation to enable learning of robotic manipulation of textiles. The latter application provides an alternative to computationally expensive vision-based pipelines and we believe it is the key to accelerate robotic learning of textile manipulation. Current smart textiles, however, maintain wired connections to external units, which impedes robotic manipulation, and lack modularity to facilitate state estimation of large cloths. In this work, we propose an open-source, fully wireless, highly flexible, light, and modular version of a piezoresistive smart textile. Its output stability was experimentally quantified and determined to be sufficient for classification tasks. Its functionality as a state sensor for larger cloths was also verified in a classification task where two of the smart textiles were sewn onto a piece of clothing of which three states are defined. The modular smart textile system was able to recognize these states with average per-class F1-scores ranging from 85.7 to 94.6% with a basic linear classifier.