Part of the book: Advanced Aspects of Spectroscopy
The authors concentrated their attention on the new area of research, concerning properties of electrically conductive textiles, produced by printing techniques. Such materials can be used for monitoring, for example, the rhythm of breathing. The aim of this study was to develop a sensor of strains for the needs of wearable electronics. A resistance‐type sensor was made on a knitted fabric with shape memory, dedicated to monitor motor activity of human. The Weftloc knitted fabric shows elastic memory—thanks to the presence of elastomeric fibers. The dependence of sensoric properties of the Weftloc knitted fabric on the values of load, its increment rate, and its direction of action was tested. Mechanical parameters including total and elastic strain, elasticity degree, and strength were also assessed. The results indicate an anisotropic character of mechanical and sensoric behaviors of the sensor showing a particularly optimal behavior during diagonal loading. Electro‐conductive properties have been imparted to the Weftloc fabric by chemical deposition of polypyrrole dopped with Cl ions. In addition, authors used as a carrier functional water dispersion of carbon nanotubes AquaCyl that was adapted in the Department of Material and Commodity Sciences and Textile Metrology for forming electrically conductive pathways by film printing method. It was assumed that the electrically conductive paths are sensitive to chemical stimuli. Studies of the effectiveness of the sensors for chemical stimuli were conducted for selected pairs of liquids. The best sensory properties were obtained for the methanol vapor—the relative resistance (Rrel.) at the level above 40%. In the case of nonpolar liquid vapor, the sensoric sensitivity of the printed fabric was much lower, with Rrel. level below 29%. Properties of the electrically conductive materials, such as thermal conductivity, electrical conductivity, and resistance to chemicals, allow for widely using them nanotechnology.
Part of the book: Printed Electronics
Polyesters occupy an important place in the group of polymers as engineering materials to be used in electrotechnology and electronics. These polymers are characterized by excellent electro-insulating properties, showing mechanical strength, thermal resistance, and easiness in processing at the same time. The chapter presents the behavior analysis of the following polyesters in electric field: poly(ethylene terephthalate), poly(lactic acid), and polycarbonate. The effect of polymer microstructure on electric properties is presented, including its susceptibility to polarization that makes it possible to use polyesters as electrets materials. The second trend of the study presents the possibilities of transforming the electro-insulating properties of polyester fabrics to conductive properties with the use of modern processing methods such as PVD, CVD, and digital print. The functionalization of polyester fabrics extends their application range, for example, in e-textiles and reduces the fabric susceptibility to static electricity, increasing the safety of use.
Part of the book: Electrical and Electronic Properties of Materials