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Abstract. This paper describes a study, which proposes an alternative and safe energy source, namely, a flexible aluminium-air battery that is suited for use in special garments and wearable products, particularly those worn by children. The need for such a battery has arisen in our recent study, in which we have developed a textile-circuitbased enuresis alarm system. The system is primarily intended for use by children while they sleep, hence the use of lithium ion or other traditional batteries poses serious safety risks. The proposed battery uses saline electrolyte and all of its elements are flexible, which makes it particularly suitable for use in such specialized arrangements, where the appearance of a physiological or other type of saline electrolyte (urine, sweat, blood) energizes and activates the system. This paper studies constructive particularities of such a battery, arrangement of its components, as well as electrical properties and possible applications in medical and smart childcare products, e.g., the enuresis alarm system, smart diapers etc. Methods of integration of the developed batteries in textile products are described, which are based on our previous experience and studies. The developed battery enables one to replace a split "sensor/processing unit" system with an energy source, which actively reacts to changes in its environment and generates electricity. Low costs of the proposed battery, as well as the availability of its main components, make it perfect for wide range of applications from human and animal care to consumer products.Keywords: aluminium-air battery, flexible battery, smart textiles, embroidery. IntroductionIn one of our previous studies, we developed a textile enuresis alarm for children [1], which is intended to be worn by children during their sleep in order to treat enuresis. One of the main issues that has arisen during the study was related to the energy source. The system had to be autonomous and it was not feasible to use external power supply. Most commercially available chemical energy sources pose a certain degree of hazard due to their components -they either contain toxic materials or even pose explosion risk if not wired properly. One of the most promising alternatives was to use aluminium-air batteries due to the advantages described below. Besides that, since these batteries can be used with saline electrolytes, it is possible to use urine or other physiological liquids for their activation. As can be seen in the experimental results below, the activation of the battery is rather fast after the liquid is applied.Aluminium-air batteries are becoming more and more popular lately due to various factors, the major two being the abundance of aluminium in the Earth crust, hence its low price, and its relatively high theoretical voltage and energy density [2; 3].Another major advantage of aluminium-air batteries is that they can be made using safe and nontoxic materials. A basic design consists of an aluminium anode and a cathode, which needs to draw oxygen for ...

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A load-bearing matrix filled with biologically active compounds is an efficient method for transporting them to the target location. Bee-made propolis has long been known as a natural product with antibacterial and antiviral, anti-inflammatory, antifungal properties, and anti-oxidative activity. The aim of the research is to obtain stable propolis/PVA solutions and produce fibers by electrospinning. To increase propolis content in fibers as much as possible, various types of propolis extracts were used. As a result of the research, micro- and nano-fiber webs were obtained, the possible use of which have biomedical and bioprotective applications. All used materials are edible and safe for humans, and fiber webs were prepared without using any toxic agent. This strategy overcomes propolis processing problems due to limitations to its solubility. The integration of different combinations of extracts allows more than 73 wt% of propolis to be incorporated into the fibers. The spinning solution preparation method was adapted to each type of propolis, and by combining the methods, solutions with different propolis extracts were obtained. Firstly, the total content of flavonoids in the propolis extracts was determined for the assessment and prediction of bioactivity. The properties of the extracts relevant for the preparation of electrospinning solutions were also evaluated. Secondly, the most appropriate choice of PVA molecular weight was made in order not to subject the propolis to too high temperatures (to save resources and not reduce the bioactivity of propolis) during the solution preparation process and to obtain fibers with the smallest possible diameter (for larger surface-to-volume ratios of nanofibers and high porosity). Third, electrospinning solutions were evaluated (viscosity, pH, conductivity and density, shelf life) before and after the addition of propolis to predict the maximum propolis content in the fibers and spinning stability. Each solution combination was spun using a cylindrical type electrode (suitable for industrial production) and tested for a stable electrospinning process. Using adapted solution-mixing sequences, all the obtained solutions were spun stably, and homogeneous fibers were obtained without major defects.

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