TY - JOUR AB - Nanofiber mats can be produced by electrospinning from diverse polymers and polymer blends as well as with embedded ceramics, metals, etc. The large surface-to-volume ratio makes such nanofiber mats a well-suited substrate for tissue engineering and other cell growth experiments. Cell growth, however, is not only influenced by the substrate morphology, but also by the sterilization process applied before the experiment as well as by the chemical composition of the fibers. A former study showed that cell growth and adhesion are supported by polyacrylonitrile/gelatin nanofiber mats, while both factors are strongly reduced on pure polyacrylonitrile (PAN) nanofibers. Here we report on the influence of different PAN blends on cell growth and adhesion. Our study shows that adding ZnO to the PAN spinning solution impedes cell growth, while addition of maltodextrin/pea protein or casein/gelatin supports cell growth and adhesion. AU - Wehlage, Daria AU - Blattner, Hannah AU - Mamun, Al AU - Kutzli, Ines AU - Diestelhorst, Elise AU - Rattenholl, Anke AU - Gudermann, Frank AU - Lütkemeyer, Dirk AU - Ehrmann, Andrea ID - 651 IS - 1 JF - AIMS Bioengineering KW - electrospinning KW - nanofiber mat KW - autoclaving KW - cell growth KW - adherent cells KW - CHO cells KW - DMSO SN - 2375-1495 TI - Cell growth on electrospun nanofiber mats from polyacrylonitrile (PAN) blends VL - 7 ER - TY - JOUR AB - Polyacrylonitrile belongs to the most often used precursors for carbon fibers. Using electrospinning, polyacrylonitrile nanofiber mats can be prepared and afterwards stabilized and carbonized to prepare carbon nanofiber mats which, by adding other materials, will be useful for several applications. One of these materials is TiO2, which has photocatalytic properties and can thus be used as a photocatalyst for photodegradation of dyes. Here, we report on a detailed study of electrospinning, stabilization, and carbonization of electrospun polyacrylonitrile/TiO2 mats with varying TiO2 content. Depending on the amount of TiO2 in the nanofibers, the fiber morphology changes strongly, indicating an upper limit for the preparation of carbon/TiO2 nanofibers with smooth surface, but offering an even increased inner surface of the rougher carbon/TiO2 nanofibers with increased TiO2 content due to better maintenance of the fibrous structure during stabilization. AU - Sabantina, Lilia AU - Böttjer, Robin AU - Wehlage, Daria AU - Grothe, Timo AU - Klöcker, Michaela AU - García-Mateos, Francisco José AU - Rodríguez-Mirasol, José AU - Cordero, Tomás AU - Ehrmann, Andrea ID - 573 JF - Journal of Engineered Fibers and Fabrics KW - Polyacrylonitrile KW - PAN KW - TiO2 KW - nanofiber mat KW - electrospinning KW - composite KW - stabilization KW - carbonization TI - Morphological study of stabilization and carbonization of polyacrylonitrile/TiO2 nanofiber mats VL - 14 ER - TY - JOUR AB - Electrospinning is a well-known technology used to create nanofiber mats from diverse polymers and other materials. Due to their large surface-to-volume ratio, such nanofiber mats are often applied as air or water filters. Especially the latter, however, have to be mechanically highly stable, which is challenging for common nanofiber mats. One of the approaches to overcome this problem is gluing them on top of more rigid objects, integrating them in composites, or reinforcing them using other technologies to avoid damage due to the water pressure. Here, we suggest another solution. While direct 3D printing with the fused deposition modeling (FDM) technique on macroscopic textile fabrics has been under examination by several research groups for years, here we report on direct FDM printing on nanofiber mats for the first time. We show that by choosing the proper height of the printing nozzle above the nanofiber mat, printing is possible for raw polyacrylonitrile (PAN) nanofiber mats, as well as for stabilized and even more brittle carbonized material. Under these conditions, the adhesion between both parts of the composite is high enough to prevent the nanofiber mat from being peeled off the 3D printed polymer. Abrasion tests emphasize the significantly increased mechanical properties, while contact angle examinations reveal a hydrophilicity between the original values of the electrospun and the 3D printed materials. AU - Kozior, Tomasz AU - Trabelsi, Marah AU - Mamun, Al AU - Sabantina, Lilia AU - Ehrmann, Andrea ID - 599 IS - 10 JF - Polymers KW - nanofiber mat KW - electrospinning KW - water filter KW - 3D printing KW - FDM printing KW - adhesion KW - stabilization KW - carbonization TI - Stabilization of Electrospun Nanofiber Mats Used for Filters by 3D Printing VL - 11 ER - TY - JOUR AB - Electrospinning is a frequently used method to prepare air and water filters. Electrospun nanofiber mats can have very small pores, allowing for filtering of even the smallest particles or molecules. In addition, their high surface-to-volume ratio allows for the integration of materials which may additionally treat the filtered material through photo-degradation, possess antimicrobial properties, etc., thus enhancing their applicability. However, the fine nanofiber mats are prone to mechanical damage. Possible solutions include reinforcement by embedding them in composites or gluing them onto layers that are more mechanically stable. In a previous study, we showed that it is generally possible to stabilize electrospun nanofiber mats by 3D printing rigid polymer layers onto them. Since this procedure is not technically easy and needs some experience to avoid delamination as well as damaging the nanofiber mat by the hot nozzle, here we report on the reversed technique (i.e., first 3D printing a rigid scaffold and subsequently electrospinning the nanofiber mat on top of it). We show that, although the adhesion between both materials is insufficient in the case of a common rigid printing polymer, nanofiber mats show strong adhesion to 3D printed scaffolds from thermoplastic polyurethane (TPU). This paves the way to a second approach of combining 3D printing and electrospinning in order to prepare mechanically stable filters with a nanofibrous surface. AU - Kozior, Tomasz AU - Mamun, Al AU - Trabelsi, Marah AU - Wortmann, Martin AU - Lilia, Sabantina AU - Ehrmann, Andrea ID - 623 IS - 12 JF - Polymers KW - electrospinning KW - 3D printing KW - FDM printing KW - nanofiber mat KW - adhesion KW - water filter SN - 2073-4360 TI - Electrospinning on 3D Printed Polymers for Mechanically Stabilized Filter Composites VL - 11 ER - TY - JOUR AB - Electrospun nanofiber mats show a very high surface-to-volume ratio as well as good mechanical properties and are thus typically used as filters or wound dressings, for drug delivery or as catalysts. Their optical properties, however, are only scarcely investigated. Due to the fine fibers with typical diameters of a few hundred nanometers, they tend to scattering visible light strongly. When wetted, however, they can become nearly invisible due to index-matching with the solvent and benefiting from the low thickness of the mats of usually only few microns. Here we report on polyacrylonitrile nanofiber mats, electrospun solely or blended with biopolymers, ceramics and other materials to modify their morphological and optical properties. Spectroscopic investigations of wetted nanofiber mats revealed different drying processes for different nanofiber morphologies and materials. On the other hand, some nanofiber mats were dissolved and the nano-mat forming process was evaluated spectroscopically, underlining the significant difference in the optical properties of nanofiber mats and nano-membranes of identical areal weights. With that we show the capability of the nanofiber mats for reversible transmission as well as permanent transmission tuning. AU - Kerker, Eugen AU - Steinhäußer, Dominik AU - Mamun, Al AU - Trabelsi, Marah AU - Fiedler, Johannes AU - Sabantina, Lilia AU - Juhász Junger, Irén AU - Schiek, Manuela AU - Ehrmann, Andrea AU - Kaschuba, Reinhard ID - 628 JF - Optik KW - Electrospinning KW - Nanofiber mat KW - Nano-membrane KW - Solvent KW - Spectroscopy KW - Scattering KW - Tunable transmittance SN - 0030-4026 TI - Spectroscopic investigation of highly-scattering nanofiber mats during drying and film formation VL - 208 ER - TY - JOUR AB - TiO2 is a semiconductor that is commonly used in dye-sensitized solar cells (DSSCs). However, the necessity of sintering the TiO2 layer is usually problematic due to the desired temperatures of typically 500 °C in cells that are prepared on polymeric or textile electrodes. This is why textile-based DSSCs often use metal fibers or metallic woven fabrics as front electrodes on which the TiO2 is coated. Alternatively, several research groups investigate the possibilities to reduce the necessary sintering temperatures by chemical or other pre-treatments of the TiO2. Here, we report on a simple method to avoid the sintering step by using a nanofiber mat as a matrix embedding TiO2 nanoparticles. The TiO2 layer can be dyed with natural dyes, resulting in a similar bathochromic shift of the UV/Vis spectrum, as it is known from sintered TiO2 on glass substrates, which indicates an equivalent chemical bonding. Our results indicate a new possibility for producing textile-based DSSCs with TiO2, even on textile fabrics that are not high-temperature resistant. AU - Ehrmann, Andrea AU - Mamun, Al AU - Trabelsi, Marah AU - Klöcker, Michaela AU - Sabantina, Lilia AU - Großerhode, Christina AU - Blachowicz, Tomasz AU - Grötsch, Georg AU - Cornelißen, Carsten AU - Streitenberger, Almuth ID - 570 IS - 7 JF - Fibers KW - TiO2 KW - dye-sensitized solar cell (DSSC) KW - textile-based DSSC KW - electrospinning KW - nanofiber mat KW - polyacrylonitrile (PAN) TI - Electrospun nanofiber mats with embedded non-sintered TiO2 for dye-sensitized solar cells (DSSCs) VL - 7 ER -