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Leather is a well-known material with a wide range of applications in clothing, footwear, protection, accessories and furnishing. Further on it is reported in only a few triboelectric series tables, as a material which has an intensive tendency to become positive. In the hereby study, its triboelectric potentials are examined to be used as part of a triboelectric generator which would be part of clothing. Natural leather from cows and sheep was used. Samples of 25 cm2 area were cut and examined together with Polytetrafluoroethylene (PTFE) material, using a prototype measuring triboelectric generator device under a force of 0.5 N. The highest Vpp values were given by the front (grain) side of cow and sheep thin samples, reaching a mean Vpp of 1293 and 1233 mV respectively. In all the tests, the front side of the samples performed better than their back (flesh) as a triboelectric surface. Additionally, the thin samples performed better than the thick ones and the less stiff samples performed better than the stiff ones. The outcoming voltages seem promising in comparison to other ordinary natural materials previously studied. The results point to the potential of leather usage in wearable triboelectric generators.

Conductive leather and its use in smart products have found a lot of interest. Leather behaves as a good insulator, so it was treated with electrically conducting polypyrrole using a chemical polymerization technique to give it conductive characteristics. The electro-conductive properties are obtained by using the double in–situ oxidative polymerization of pyrrole. The electrical properties of conductive samples are studied using the Van Der Pauw method as a measuring method. The conductive leather transformation process was carried out during the 2018-2020 period, and the conductive leather samples were preserved in room conditions until the year 2023. The effect of natural ageing on the electro-conductive properties of conductive leather is the focus of this research. The results show that environmental factors influence polymer breakdown and stability, by causing an increase in electrical resistance. The changes in electrical surface resistance, as the effect of the ageing factor, vary from 39.8% to 129.9%. Those changes in electrical resistance indicate that ageing is one of the major concerns in the electrical properties and stability of conductive leather samples, so the performed measurements have importance in providing information for the researchers and designers regarding the conductivity changes over time as a result of natural ageing, which would like to work with conductive leather on smart products.

The Internet of Things (IoT) is considered a promising realm of innovation and revenue generation for the forthcoming years, revolutionizing the way we interact with objects, other people and the world. With an unprecedented but realistic target of trillions of interconnected devices, the IoT calls for technological innovations that lie in the heart of rapid, low-energy and user-friendly communication between people and things. In this respect, the Near Field Communication (NFC) protocol offers advanced efficiency and applicability with low energy consumption, ease of use, flexibility, and increased payload. NFC tags may be embedded in everyday objects, including clothing and apparel, offering an immersive user experience. Wearable NFC antennas and NFC tags embedded in clothing have been presented in the past; nonetheless, in this paper we present, to the best of our knowledge, the first reported development of a NFC antenna on leather substrate. The proposed antenna is sewn using stainless steel thread and operates at the 13.56 MHz frequency range. It may be used alongside with NFC tags in leather apparel like clothing, shoes, accessories, etc., thus extending the possible use cases and applications of the NFC technology and offering an all the more immersive experience for the end user.

A mathematical model is presented to simulate the electric resistivity of leather samples as a function of humidity. It will be shown that absolute and not relative humidity is the crucial parameter. The model assumes that the leather includes channels that can absorb water from the surrounding environment. This effect primarily determines the electric conductivity of the leather samples. The theoretical results from the model are quite closely in line with experimental measurements.

Electro-conductive textiles are mostly fabrics that have conductive elements or electronics integrated into them to achieve electrical characteristics. They have acquired considerable attention in applications involving sensors, communications, heating textiles, entertainment, health care, safety etc. To produce electro-conductive textiles, several techniques, e.g. chemical treating with conductive polymers on various textile materials, or using different technologies, e.g. knitting, weaving, embroidery techniques to include conductive threads into fabric interconnections etc., are being used. Electro-conductive fabrics are flexible enough to be adapted to quick changes in any particular application, beginning with wearable purposes and sensing needs as specified by many different groups. The ability of electro-conductive textiles to conduct electricity is the most essential property they must possess. In addition, the applications that may be worn should have stable electrical, thermal and mechanical qualities. The most recent developments in the field of electro-conductive textiles represent the aim of this review, which analyses these properties, including the investigation of methods that are used to obtain conductive textiles, their electrical properties, thermal properties, and beyond that, the scientific methods that are used to measure and investigate electro-conductive textiles. We also focused on the textile materials used in studies, as well as the technologies used to make them conductive, which may be a guide for different interested groups for use in a variety of smart applications.

Leather is a material that has been used in different applications for centuries. Today, living in the era of high-tech­nology, we are surrounded by smart products. For this reason, traditional products must be changed or im­proved in order to support and make us more comfortable while using them. For instance, the touch screen display in electronics products is a smart phone’s or a tablet computer’s primary input device. Still, traditional leather will not function properly in a cold climate or other specific conditions. To make it conductive in such conditions, the double in-situ polymerization of the pyrrole coating method was used. The aim of this study was to observe the electrical properties of conductive leather. At the same time, it stands up to a wide range of different air temperatures, and relative and absolute humidity. These properties are essential because de­signers and textile engineers should be familiar with them when they decide to use materials in different smart products. Electricity conductivity tests were carried out in year-round temperatures from 7.5 °C to 28.1 °C, with a relative humidity from 18% to 77% and a vapor air concentration from 2.77 g/kg to 12.46 g/kg. The so-called “multiple-step method” was used to test leather’s electrical resistivity for the first time. The method considers a material’s compressional properties and provides an indicator inherent for a material’s electrical properties, regardless of the mass and shape of samples. The results showed a strong dependence between water vapor air concentration and electrical resistivity, described using the formula ρ = 1.3103 H−1.04 Ωm, with a correlation coefficient of 0.87. There was no relation between relative humidity and electrical resistivity, and resistivity and air temperature. Also, the results confirmed again that changes in the shape of the sample used during tests did not influence the measurement’s results, but supported the appropriateness of the measuring method.

In the last decade, smart textiles have become very popular as a concept and have found use in many applications, such as military, electronics, automotive, and medical ones. In the medical area, smart textiles research is focused more on biomonitoring, telemedicine, rehabilitation, sport medicine or home healthcare systems. In this research, the development and localization accuracy measurements of a smart T-shirt are presented, which will be used by elderly people for indoor localization in ambient assisted living applications. The proposed smart T-shirt and the work presented is considered to be applicable in cases of elderly, toddlers or even adults in indoor environments where their continuous real-time localization is critical. This smart T-shirt integrates a localization sensor, namely the Localino sensor, together with a solar panel for energy harvesting when the user is moving outdoors, as well as a battery/power bank that is both connected to the solar panel and the Localino sensor for charging and power supply respectively. Moreover, a mock-up house was deployed, where the Localino platform anchors were deployed at strategic points within the house area. Localino sensor nodes were installed in all the house rooms, from which we obtained the localization accuracy measurements. Furthermore, the localization accuracy was also measured for a selected number of mobile user scenarios, in order to assess the platform accuracy in both static and mobile user cases. Details about the implementation of the T-shirt, the selection and integration of the electronics parts, and the mock-up house, as well as about the localization accuracy measurements results are presented in the paper.

Determining the surface resistance of electro conductive refined natural leather materials is in the focus of this paper. Natural leather samples are initially transformed to conductive by applying chemical treatment process known as polymerization. Due to the existence of various techniques for measuring electrical resistance of conductive materials, we are focused on measuring surface resistance by arranging four electrodes in the edges of square leather samples, also known as Van der Pauw method. Improving the results accuracy, we use a multi-variant electrode placement over the sample edges. The result is the average of all results gained for different placements. Moreover, we use this electrode placement technique to analyse the anisotropy of conductive samples. The results of this research provide important knowledge about leather chemical treatment and its electrical proprieties.

Measurement of electrical resistance of textile materials, fiber and fabrics included, remains always an engaging task due to sensitivities to interference of multiple factors. Difficulty stands on both finding a method of measurements that fits the requirements of samples to be tested and the most appropriate indicator describing this property. Numerous methods and indicators are used for different sample content and shape (fibers, roving, yarn or fabric, etc.), even when the material tested is the same. Different methods usually use indicators that produce results difficult to compare or to interpret, or do not express intrinsic qualities of their constituent materials. The situation is the same for leather materials. In this paper, we propose a new method, multiple steps method, and a new indicator, electrical resistivity, which takes into consideration compressional properties of leather sample and produce results independent from the amount and form of the sample. Electrical resistivity of conductive leather, as defined below, is shown to be an inherent indicator of bulk conductivity of leather assembly and is not influenced by sample form or the way it is placed within the measuring cell. The method is used for the first time to evaluate changes in electrical resistivity of leather after various chemical processes to make it electro-conductive. The data provide important information about the evolution of electro-conductive properties of leather at different stages of processing, as well as the influence of environmental conditions.

In the summer of 2018, the Balkan Society of Textile Engineers (known as BASTE) has been established. It reflects the will of the communities of the textile engineers in the Balkan countries to strengthen and enhance their cooperation.