ABSTRACT
The work is framed within Printed Electronics, an emerging technology for the manufacture of electronic products. Among the different printing methods, the roll-to-roll flexography technique is used because it allows continuous manufacturing and high productivity at low cost. Nevertheless, the incorporation of the flexography printing technique in the textile field is still very recent due to technical barriers such as the porosity of the surface, the durability and the ability to withstand washing. By using the flexography printing technique and conductive inks, different printings were performed onto woven fabrics. Specifically, the study is focused on investigating the influence of the structure of the woven fabric with different weave construction, interlacing coefficient, yarn number and fabric density on the conductivity of the printing. In the same way, the influence of the weft composition was studied by a comparison of different materials (cotton, polyester, and wool). Optical, SEM, color fastness to wash, color measurement using reflection spectrophotometer and multi-meter analyses concluded that woven fabrics have a lower conductivity due to the ink expansion through the inner part of the textile. Regarding weft composition, cotton performs worse due to the moisture absorption capacity of cellulosic fiber. A solution for improving conductivity on printed electronic textiles would be pre-treatment of the surface substrates by applying different chemical compounds that increase the adhesion of the ink, avoiding its absorption.
ABSTRACT
Long-term wounds need a continuous assessment of different biophysical parameters for their treatment, and there is a lack of affordable biocompatible devices capable of obtaining that uninterrupted flow of data. A portable prototype that allows caregivers to know the local temperature behavior of a long-term wound over time and compare it with different reference zones has been developed. Alternative flexible substrates, screen-printing techniques, polymeric inks, and an embedded system have been tested to achieve potential indicators of the status and evolution of chronic wounds. The final system is formed by temperature sensors attached to a flexible and stretchable medical-grade substrate, where silver conductive tracks have been printed as interconnections with the data-acquisition unit. In addition, a specific datalogger has been developed for this system. The whole set will enable health personnel to acquire the temperature of the wound and its surroundings in order to make decisions regarding the state and evolution of the wound.
