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

Printed Textiles with Chemical Sensor Properties

In this study the authors proposed the introduction of chemical sensors directly on textile surfaces in the form of conductive transmission parts using the screen-printing technique. A liquid vapour-sensitive, printing surface made with the use of multi-walled carbon nanotubes was also evaluated. Carbon nanotubes show effective chemo-sensory properties because the chemical agent leads to changes in electrical conductivity. The research concerned the assessment of sensor efficiency for chemical incentives in the form of selected fluids and their vapours. The best sensory properties were observed for polar vapour at a level of relative resistance over 40%. In the case of vapours of non-polar fluids the sensory reaction of the printed fabrics is much weaker – at a level of relative resistance of about 25%. The printed textile backings subjected to the influence of a fluid show an immediate reaction, while in the case of fluid vapour the reaction occurs after a few seconds. Detection of the presence of dangerous chemical agents such as organic liquids and their vapour is possible by means of a structure composed of sensors

Technologies Involved in the Manufacture of Smart Nonwoven Fabrics

Many methods can be used to protect humans against hazardous chemicals in the environment such as personal protective equipment and protective clothing. However, what matters most is prevention and early detection of threats. Detecting the presence of hazardous chemicals such as organic liquids and the vapours they give off is possible using sensors. Effective chemosensory properties are revealed by conductive polymers and carbon 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 sensitivity, 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 produced 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 carbon 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

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 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

Wybrane zagadnienia z metrologii użytkowej odzieży funkcjonalnej

Politechnika Łódzka. Wydział Technologii Materiałowych i Wzornictwa Tekstyliów. Katedra Materiałoznawstwa, Towaroznawstwa i Metrologii Włókienniczej.Lodz University of Technology. Faculty of Material Technologies and Textile Design. Department of Material and Commodity Sciences and Textile Metrology.Rozwój technologii nowych materiałów, sposobu ich przetwarzania i wykorzystywania, a także coraz lepsze poznanie mechanizmów zachodzących w organizmie człowieka sprzyjają rozwojowi odzieży specjalnego przeznaczenia. Odzież już nie stanowi wyłącznie bariery przed zimnem, ale również ma za zadanie stanowić barierę przed czynnikami szkodliwymi, skrajnymi warunkami termicznymi, a także wspomagać funkcjonowanie organizmu jej użytkownika w warunkach ekstremalnych. Obecnie coraz większą uwagę zwraca się na zachowanie optymalnych warunków, w jakich powinien żyć i pracować człowiek, ponieważ zostało potwierdzone, że manualne i intelektualne zdolności człowieka osiągają swoje optimum w warunkach komfortu cieplnego. W tym kontekście problem odzieży ochronnej zapewniającej optymalny komfort cieplny użytkownika nabiera szczególnego znaczenia.Prace badawcze do prezentowanej książki były współfinansowane z Projektu pt. „Optymalizacja struktury ubioru ochronnego dla noworodków urodzonych przedwcześnie przy zastosowaniu oryginalnych narzędzi wspomagających proces projektowania” UMO-2011/03/B/ST8/06275, finansowanego przez Narodowe Centrum Nauki i Projektu pt. „Nowoczesne ochrony osobiste służb ratowniczych KSRG w oparciu o potrzeby użytkowników końcowych”, O ROB 0014 01/ID14/1, finansowanego przez Narodowe Centrum Badań i Rozwoju oraz z prac statutowych Wydziału Technologii Materiałowych i Wzornictwa Tekstyliów, Politechniki Łódzkiej

Graphene printing for textronic devices

Grafen se dokazao kao izvrstan nanomaterijal za suvremene elektroničke namjene kao što su biosenzori, tranzistori ili grijači. Nastojanja su da se ovaj novi nanomaterijal upotrebljava za razvoj jedinstvenih tekstroničkih uređaja. Trenutno stanje znanosti o materijalima pokazuje mogućnosti dizajna pametnih tekstila s grafenom. Autori iznose rezultate primjene 2D ugljikove strukture u tekstroničkim uređajima. Primjena novorazvijenih tinti i pasta daju zanimljiva svojstva tekstilu kao što su električna vodljivost i osjetljivost na hlapljive organske spojeve.Graphene has been proved to be an excellent nanomaterial for modern electronic applications such as biosensors, transistors or heaters. The natural point of view is to use this new nanomaterial for the development of unique textronic devices. The current state of the art of the materials science shows design possibilities of the smart textiles with graphene. The authors show the results of implementation of 2D carbon structure into the textronic devices. The development inks and pastes give interesting properties of textile such as electro conductivity and sensitive to the volatile organic compounds

Study of Influence of Atmospheric Conditions on the Thermal Properties of Sleeping Bags

The thermal properties of clothing products are influenced by external environmental parameters, such as temperature, humidity, air flow and parameters related to the user’s body, which mainly include temperature and humidity. Depending on the type of raw material, its thickness and the material manufacturing technique, clothing products are characterised by certain insulating properties to protect the human body from external factors. A multilayer system made of different material groups can change the thermal insulating capacity significantly, which cannot be determined by the testing of individual layers used in the production. In order to determine the influence of weather conditions on thermal insulation and air permeability, tests were carried out for two types of sleeping bags (summer and autumn) produced by the same manufacturer, differing in insulation thickness. Simulations were carried out using SolidWorks and verified using a Newton thermal mannequin. During tests, both the temperature (range from −20 °C to 20 °C) and humidity values were changed (range 40–80% humidity). For sleeping bags, the effective thermal insulation decreases along with the increase of temperature and decrease of humidity. It can be observed, for the autumn sleeping bags, that for a temperature of 20 °C and humidity of 60%, the thermal insulation is 1.063 m2·K·W−1, while for a temperature of −20 °C and humidity of 60% thermal insulation increases significantly and amounts to 1.111 m2·K·W−1. A similar situation occurs for the effective thermal insulation of a summer sleeping bag (20 °C/60% thermal insulation is 0.794 m2·K·W−1, while for −20 °C/60%—0.851 m2·K·W−1. During the tests, the humidity and temperature between the layers of the clothing system were also controlled, in order to learn more about the influence of these parameters on the thermal insulation properties of the sleeping bags

Changes in the education of teachers of early childhood education in the 21st century in Poland

The article presents the issue of educating teachers of preschool and early childhood education in Poland against the background of social changes after 1989. Despite efforts to provide teachers with full higher education, regulations made it possible to employ people without a master’s degree to work with children. This was due to the lack of teachers of a given specialisation and resulted from certain legal solutions in higher education. Many universities offered faculties and specialisations in this area, but failed to fully ensure a sufficient level of education. The text presents negative phenomena related to the lack of proper education standards. Recent changes in the standards of teacher preparation have forced an increase in the level of requirements for the education of preschool teachers, but the author remains doubtful about some solutions