Ewa Skrzetuska

Chemically Driven Printed Textile Sensors Based on Graphene and Carbon Nanotubes

The unique properties of graphene, such as the high elasticity, mechanical strength, thermal conductivity, very high electrical conductivity and transparency, make them it an interesting material for stretchable electronic applications. In the work presented herein, the authors used graphene and carbon nanotubes to introduce chemical sensing properties into textile materials by means of a screen printing method. Carbon nanotubes and graphene pellets were dispersed in water and used as a printing paste in the screen printing process. Three printing paste compositions were prepared—0%, 1% and 3% graphene pellet content with a constant 3% carbon nanotube mass content. Commercially available materials were used in this process. As a substrate, a twill woven cotton fabric was utilized. It has been found that the addition of graphene to printing paste that contains carbon nanotubes significantly enhances the electrical conductivity and sensing properties of the final product.

Application of melt-blown technology in the manufacturing of a solvent vapor-sensitive, non-woven fabric composed of poly(lactic acid) loaded with multi-walled carbon nanotubes

We evaluated a solvent vapor-sensitive, non-woven fabric made from a biodegradable, poly(lactic acid) (PLA) polymer loaded with multi-walled carbon nanotubes. The sensory properties of the fabric were obtained by optimizing the process parameters for manufacturing the melt-blown, non-woven fabric composed of 98% PLA 4060D (Nature Works) and 2% multi-walled carbon nanotubes (Nanocyl®). The diffusion of polar and non-polar solvent molecules influenced the electron flow between the separated carbon nanotubes in percolation paths built into the PLA, resulting in an increase of the resistance of the melt-blown, non-woven fabrics. The statistically significant differences between the mean values of electrical resistance before and after the influence of the tested solvent vapors were achieved for the non-woven fabrics manufactured at high air velocity and low extruder screw speed, taking the values of 30 m3/h and 20 rpm, respectively. The results obtained for the non-woven fabric manufactured in the optimal conditions show that methanol vapor response has the lowest amplitude of 15%, whereas for benzene, acetone and toluene sensitivity reaches values of 60%, 40%, and 35%, respectively. The values of the relative resistance amplitude correspond with Flory–Huggins interaction parameters κPLA\benzene < κPLA\acetone < κPLA\toluene < κPLA\methanol.

Giving Functional Properties to Fabrics Containing Polyester Fibres from Poly (Ethylene Terephthalate) with the Printing Method

© 2012 Skrzetuska et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Giving Functional Properties to Fabrics Containing Polyester Fibres from Poly (Ethylene Terephthalate) with the Printing Method

Application of a Thermal Mannequin to the Assessment of the Heat Insulating Power of Protective Garments for Premature Babies

Abstract In this study, the new tool for measuring thermal insulating power of garments for premature babies under coupled heat and moisture transport was developed. The thermal mannequin corresponds to the body weight and size of a premature baby born in the thirty fourth week of pregnancy. The mannequin surface temperature can be set at various levels, while the heat loss is measured in W/m2. The mannequin is divided into eleven independent heating zones and seven independent zones of moisture evolution. The study also presents the test results of heat insulating power obtained for the newly developed garment set with commercially available garment set for babies, conducted under different climatic conditions. The results exhibit the advantage of the new material construction of the garment over the commercially available one.

Development Trends in Electronics Printed: Intelligent Textiles Produced with the Use of Printing Techniques on Textile Substrates

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 effective‐ ness 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 sensitivi‐ ty 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.

Technologies Involved in the Manufacture of Smart Nonwoven Fabrics

Many methods can be used to protect humans against hazardous chemicals in the envi‐ ronment such as personal protective equipment and protective clothing. However, what matters most is prevention and early detection of threats. Detecting the presence of haz‐ ardous chemicals such as organic liquids and the vapours they give off is possible using sensors. Effective chemosensory properties are revealed by conductive polymers and car‐ bon particles, where the electrical resistance of chemicals changes. Still open to debate is finding the optimum means of applying chemical sensors that would provide high sensi‐ tivity, durability, reliability, and resistance but at the same time would not be expensive. The authors propose introducing chemical sensors in the form of nonwoven fabrics pro‐ duced by the melt-blown method and by electrospinning. The analysis takes account of melt-blown nonwoven fabric based on polylactide (PLA)-containing carbon nanotubes, nonwoven fabric made by electrospinning based on polyethylene oxide–containing car‐ bon nanotubes and carbon nonwoven fabric from polyacrylonitrile submicron precursor fibres formed by electrospinning. Assessment of the effectiveness of the sensors to liquid vapours including methanol, acetone, benzene and toluene (concentration 200 ppm) has been carried out. The resulting nonwoven sensors are characterized by good electrical conductivity and altered electrical resistance as a result of the presence of vapours.

The Possibilities of Graphenes Application in Textronic Devices

Graphene, because of its exceptional properties such as very good electrical conductance, flexibility and high optical transparency in visible light spectrum, has proved to be an excellent nanomaterial for modern electronic applications. The natural point of view is to use this new nanomaterial for the development of unique textronic devices such as sensory systems for monitoring human body’s vital functions and atmospheric composition. The present review shows the state of art of materials science and possibilities of the smart textiles design with graphene. The most promising applications of graphene for the design of textronic devices are the development of conductive polymer composites (CPC) and the development of inks and pastes for printing conductive tracks on textile materials. The preliminary results of implementation of 2D carbon structure into textronic devices are presented.