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Nanofiber mats with a high surface-to-volume ratio can be prepared by electrospinning. The Porosity is sometimes reported to be tunable by blending different materials, e.g., water-soluble poly(ethylene oxide) (PEO) with not water-soluble poly(acrylonitrile) (PAN). Here, nanofiber mats were electrospun from different PAN:PEO ratios, using a wire-based electrospinning machine "Nanospider Lab". Investigations of the as-spun nanofiber mats as well as of membranes after washing off the water-soluble PEO by scanning electron microscopy (SEM) revealed severe differences in the nanofiber mat morphologies, such as varying fiber diameters and especially non-fibrous areas in the carbonized nanofiber mats, depending on the amount of PEO in the nanofiber mat as well as the molecular weight of the PEO. Similarly, the ratio and molecular weight of PEO influenced the results of stabilization and carbonization. This paper discusses the possibility of tailoring nanofiber porosity for the potential use of PAN nanofiber mats in tissue engineering, filtration, and other applications. [ABSTRACT FROM AUTHOR]

Composites of textile fabrics and 3D-printed layers have been investigated thoroughly during the last decade. Usually, material extrusion such as the fused deposition modeling (FDM) technique is used to build such composites, revealing challenges in preparing form-locking connections between both materials due to the highly viscous polymer melt, which can hardly be pressed into textile fabrics. Resins used for 3D printing by vat photopolymerization, i.e., for stereolithography (SLA), are less viscous and can thus penetrate deeper into textile fabrics; however, fixing a textile on the printing bed that is fully dipped into the resin is more complicated. Here, we present one possible solution to easily fix textile fabrics for SLA printing with consumer printers according to the digital light processing (DLP) sub-method. Also, we show the results of a study of the mechanical properties of the resulting textile/polymer composites, as revealed by three-point bending tests. [ABSTRACT FROM AUTHOR]

Copyright of Tekstilec is the property of University of Ljubljana, Faculty of Natural Sciences & Engineering, Department of Textiles and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Marine macroalgae are cultivated for diverse applications, from biofuel and biogas to biofiltering, from food to cosmetics or pharmaceuticals. Since macroalgae cultivation does not compete with land-based food crops for the necessary arable land or fresh water, it can increase the possibilities of sustainably harvested biomass. New technologies permit even land-based growing of marine macroalgae, besides the more common coastal or offshore cultivation. All these technologies, however, raise the question of how to provide ideal cultivation conditions, especially for adherent macroalgae, and of how to harvest them economically and sustainably. While some reports about growing marine macroalgae on diverse textile materials, such as polyester ropes or polypropylene nets, can be found in the literature, we report here for the first time on the growth of a marine macroalga on knitted fabrics. In our study, Ectocarpus sp. was cultivated in shallow rectangular cultivation vessels on knitted fabrics of various materials and structures revealing a significant influence of both parameters. Undesired changes of the pH value in the cultivation system as well as foam generation were attributed to textile auxiliaries. Considering all these influences, the best-suited knitted fabrics were identified as open-pore structures from hairy yarns made partly or completely from natural fibres. [ABSTRACT FROM AUTHOR]

Long-term stability belongs to the main problems of dye-sensitized solar cells (DSSCs), impeding their practical application. Especially the usually fluid electrolyte tends to evaporation, thus drying the cells if they are not perfectly sealed. While gelling the electrolyte with different polymers often reduces the efficiency, using a glycerol-based electrolyte was already shown to result in similar or even improved efficiency. At the same time, drying of the cells was significantly reduced. Here we report on improving glycerol-based electrolytes further by varying the iodine-triiodide ratio and the overall concentration in the electrolyte. Long-term tests with unsealed glass-based DSSCs were performed over more than 1 year, showing that most of the cells increased efficiency during this time, opposite to cells with a commercial solvent-based iodine-triiodide electrolyte which completely dried after 2-3 months. [ABSTRACT FROM AUTHOR]

With a growing world population and the concentration of citizens in big cities new methods of agriculture are required. Vertical farming attracts more attention in mending these growing problems. To enable a widespread use of low-cost hydroponic systems this study investigates minimal requirements for plants (different herbs and vegetables) in such a hydroponic vertical farming system and the suitability of textiles as sustainable substrates. Therefore, this study aims to investigate plant stress levels, germination rates and water usage in a low-cost hydroponic system with no special lightning in principle comparison with indoor cultivation in soil. The results of the pulse-amplitude-modulation (PAM) measurements as measure of photosynthetic performance indicate that the plants were equally stressed in hydroponic and in soil cultivation. In this respect, the photosynthetic quantum yield in both cultivation systems is on average only slightly lower than the values expected under optimal conditions. It was observed that chive and lovage not only had a significantly higher germination rate in the hydroponic system but also accumulated significantly more fresh as well as dry biomass, while spinach, thyme and marjoram showed higher germination rates in soil cultivation. The water consumption in the setup was considerably higher for the hydroponic system compared to indoor soil cultivation. [ABSTRACT FROM AUTHOR]

The green microalgae Chlorella vulgaris can be used in diverse applications from food to biofuel production. Growing them in suspension leads to challenging harvesting and processing. One possibility to overcome these problems is growing them as biofilms, i.e. adhering on a surface. While previous experiments of several research groups concentrated on flat, rigid surfaces, partly chemically modified, here the possibility to grow them on different textile substrates was investigated which were shown to be suitable as substrates for germination and growth of higher plants. Microalgae were counted after one week, subdivided into adhered and suspended ones, to evaluate the ideal substrate for cultivation and harvesting. The results show clear differences between the different woven and knitted fabrics from diverse materials, indicating that especially an open-pore jute woven fabric increased the overall algae concentration by approx. a factor of 2 and increased the adhesion of C. vulgaris by a factor of 5-10, as compared to most other textile substrates under investigation, followed by two other hairy knitted fabrics. Such textile fabrics can thus be suggested as possible substrates for improved growth and harvesting of this microalga. [ABSTRACT FROM AUTHOR]

The combination of textiles and three-dimensional printing offers a wide range of research and application areas, but only publications in combination with fused deposition modeling processes can be found so far. In this article the possibility of printing resin directly on textiles in the stereolithography process is presented. A broad spectrum of textiles and surfaces is examined to clearly present the feasibility. It was found that printing directly on most textiles can be performed without major difficulties, while problems were only observed on smooth surfaces and coatings on textiles. [ABSTRACT FROM AUTHOR]

Copyright of Tekstilec is the property of University of Ljubljana, Faculty of Natural Sciences & Engineering, Department of Textiles and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study we report for the first time about the preparation of polyacrilontrile (PAN)/konjac glucomannan (KGM) nanofiber mats, needleless electrospinning from the low-toxic solvent dimethyl sulfoxide (DMSO) and the formation of carbon nanocomposites. Konjac glucomannan is a biopolymer and renewable, environmentally friendly raw material and a well-known polysaccharide, which is non-toxic and biocompatible material and is extracted from the Amorphophallus konjac plant. The addition of poloxamer in electrospinning PAN/KGM solution resulted in the reduction of membrane areas and decrease of beads in nanofibers. The concentration of 1.5% or 0.5% of konjac glucomannan in PAN/KGM nanofiber mats was not detected to affect the morphology of the nanofiber mats. The PAN/KGM nanofiber mats received oxidative stabilization and subsequent carbonization. It could be observed that after the oxidative stabilization process the average diameter of PAN/KGM nanofibers increased and after carbonization decreased compared to stabilized nanofibers. Alternative renewable raw materials such as KGM electrospun with synthetic polymers offer the possibility to reduce the environmental impact and are the alternative to new technical materials and lowers the cost of carbon materials. The combination of PAN with konjac glucomannan and the properties of both polymers open up a wide range of applications for the PAN/KGM nanofiber mats and carbon nanocomposites produced in this study, for example, for pharmaceutical and biomedical applications, as absorbents for the removal of pollutants in wastewater and as filter media for air purification, as well as for optical and chemical sensors. [ABSTRACT FROM AUTHOR]

Copyright of Tekstilec is the property of University of Ljubljana, Faculty of Natural Sciences & Engineering, Department of Textiles and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During electrospinning, the flying nanofibers can be attracted by conductive areas such as copper tape on a nonconductive substrate, especially in case of magnetic nanofibers. The question arises, however, whether the conductivity or any other physical properties of these areas are responsible for this effect. Here, electrospinning polyacrylonitrile (PAN) on nonconductive polypropylene (PP) substrates is reported, modified with conductive copper tape as well as with diverse coatings with varying dielectric constants. The results show that in case of non‐magnetic PAN fibers, especially BaTiO3 with its high dielectric constant strongly, attracts the fibers formed during electrospinning, which can be explained by local modification of the electric field due to the introduced dielectric. This process can be used to tailor the nanofiber mat thickness depending on the position. [ABSTRACT FROM AUTHOR]

To overcome the long-term stability problems of dye-sensitized solar cells (DSSC) due to solvent evaporation and leakage, gelling the electrolyte with polymers is an appropriate option. Especially for future applications of textile-based DSSCs, which require cost-effective and environmentally friendly materials, such an improvement of the electrolyte is necessary. Therefore, the temporal progressions of efficiencies and fill factors of non-toxic glass-based DSSCs resulting from different gel electrolytes with poly(ethylene oxide) (PEO) are investigated over 52 days comparatively. Dimethyl sulfoxide (DMSO) proved to be a suitable non-toxic solvent for the proposed gel electrolyte without ionic liquids. A PEO concentration of 17.4 wt% resulted in an optimal compromise with a relatively high efficiency over the entire period. Lower concentrations resulted in higher efficiencies during the first days but in a poorer long-term stability, whereas a higher PEO concentration resulted in an overall lower efficiency. Solvent remaining in the gel electrolyte during application was found advantageous compared to previous solvent evaporation. In contrast to a commercial liquid electrolyte, the long-term stability regarding the efficiency was improved successfully with a similar fill factor and thus equal quality. [ABSTRACT FROM AUTHOR]

Electrospinning can be used to create nanofibers from diverse polymers in which also other materials can be embedded. Inclusion of magnetic nanoparticles, for example, results in preparation of magnetic nanofibers which are usually isotropically distributed on the substrate. One method to create a preferred direction is using a spinning cylinder as the substrate, which is not always possible, especially in commercial electrospinning machines. Here, another simple technique to partly align magnetic nanofibers is investigated. Since electrospinning works in a strong electric field and the fibers thus carry charges when landing on the substrate, using partly conductive substrates leads to a current flow through the conductive parts of the substrate which, according to Ampère's right-hand grip rule, creates a magnetic field around it. We observed that this magnetic field, on the other hand, can partly align magnetic nanofibers perpendicular to the borders of the current flow conductor. We report on the first observations of electrospinning magnetic nanofibers on partly conductive substrates with some of the conductive areas additionally being grounded, resulting in partly oriented magnetic nanofibers. [ABSTRACT FROM AUTHOR]