Emriye Perrin Akçakoca Kumbasar

This study explores the potential of lanolin‐loaded nanofiber mats as an innovative material for skin‐contact biomedical applications, summarizing their development and biocompatibility assessment. Lanolin‐loaded cellulose acetate (CA) and thermoplastic polyurethane (TPU) nanofibers, produced via electrospinning, exhibited promising morphological properties and were compared. Following sterilization, extracts of these nanofibers were prepared at various concentrations (100%, 50%, 25%, 12.5%, and 6.25% v/v) and evaluated for cytotoxicity using the MTT assay. Two cell lines were utilized for in vitro testing: the L929 mouse fibroblast cell line, as recommended by ISO 10993‐5 to represent mammalian systems, and the HS2 human keratinocyte cell line. Results indicated that lanolin positively influenced cell viability and proliferation, with TPU/Lanolin nanofibers achieving the best outcomes. Based on these results, analyses were continued with the TPU/lanolin nanofibers, which showed better performance. Optimization studies revealed that a 3–5 h collection period and a lanolin concentration of 30% (w/w) yielded optimal results. The addition of lanolin minimally impacted air permeability, which remained low across all samples, without compromising water permeability. The most promising configuration was found to be TPU/30Lanolin‐5h. These findings suggest that, upon further validation, such lanolin‐loaded nanofiber mats hold promise for future use in healthcare products designed to promote skin comfort and healing.

Cross‐linking of polyvinyl alcohol (PVA) and polyvinyl alcohol/Nafion (PVA/Nafion) electrospun nanofibers with sulfosuccinic acid (SSA) was investigated to assess their characterization and the effects of cross‐linking on the methanol permeability performance of the nanofibrous membranes. SSA was directly incorporated into the electrospinning polymer solution. The morphology, chemical functional groups, thermal stability, water stability and water swelling of the resulting nanofibers were examined. The effects of SSA concentration on ion exchange capacity (IEC) and methanol permeability of the nanofibrous membranes were discussed. Bead‐free and smooth nanofibers were produced for all SSA concentrations with a mean nanofiber diameter of 240–270 nm. It was shown that 15% SSA concentration was suitable for preserving the morphology of PVA nanofibers against water, while the morphology of PVA/Nafion nanofibers was preserved even without cross‐linking. The increase in SSA concentration led to increase in swelling in water. SSA cross‐linking was also shown to increase the thermal stability of the produced nanofibers. IEC increased by the increase in SSA concentration, while increase in SSA concentration led to a decrease in methanol permeability.

In this study, polyvinyl alcohol/Nafion nanofibrous composite membranes were produced to investigate their possible application as a polymer electrolyte membrane (PEM) in direct methanol fuel cells. Electrospinning method was used for nanofibrous membrane production, in which the mixture of polyvinyl alcohol (PVA) and Nafion solutions was directly electrospun. Produced nanofibers were subjected to physical stabilization, filler application, and sulfonating to produce composite nanofibrous membranes. PVA and Nafion polymers were used also as filler materials. The properties of resultant composite membranes were compared in terms of water swelling, weight loss in water and methanol solution, thermal stability, morphology, proton conductivity, and methanol permeability. Proton conductivity of the membranes depending on the humidity was also investigated. TGA analysis showed that the membranes had adequate thermal properties regardless of the filler material. The nanofibrous structure was shown to be preserved by scanning electron microscopy (SEM) after treatment with water and methanol solution. It was shown that PVA/Nafion nanofibers displayed proton conductivity after filling process. The use of PVA as a filler material led to higher proton conductivity at 100 RH%. It was reported that proton conductivity could only be obtained at higher relative humidity values (>80% RH). A lower methanol permeability of PVA‐filled membranes was reported. Highlights: PVA/Nafion nanofibrous membranes were produced by electrospinning. PVA and Nafion were also used as pore filling materials. PVA‐filled membranes had higher proton conductivity and lower methanol permeability. Proton conductivity could only be obtained at higher RH% values.

In this study, the adsorption of reactive and direct dyes from synthetic textile wastewater using organobentonites modified by two different routes was studied. Except for the drying step, the synthesis conditions were the same, and organobentonites were synthesized by employing a cationic surfactant at a level corresponding to the entire cation exchange capacity of bentonite under microwave irradiation. In the final step, the samples were dried using either a freeze dryer or an air dryer. The structural characteristics of the organobentonites were determined via XRD and FTIR analyses. The obtained equilibrium data indicated that the adsorption process fitted to the Langmuir isotherm model for both dyes. Although the results indicated that both organobentonites adsorbed two of the dyes, the freeze-dried sample could serve as a more effective adsorbent for removing reactive and direct dyes from wastewater.

The purpose of UV sensors is to detect ultraviolet radiation, which is crucial for various applications, such as skin protection, environmental monitoring, and industrial processes where UV exposure poses risks. These sensors provide real‐time data to ensure safety and optimize performance in relevant fields. In this context, the aim of this study was to develop easy‐to‐use UV sensors using photochromic nanofibrous materials. Photochromic nanofibers were obtained by electrospinning thermoplastic polyurethane and a spirooxazine dye. Two solvent systems (only dimethylformamide and a dimethylformamide:dichloromethane mixture) and three dye concentrations (0.5%, 2%, and 5%) were used to produce the nanofibers. Uniform and bead‐free nanofibers were obtained using a dimethylformamide:dichloromethane solvent system. The fatigue resistance of the photochromic nanofibers was tested, revealing a maximum color loss of 14% after 20 on‐off UV cycles. Nanofibers produced with a dimethylformamide:dichloromethane solvent system and a 0.5% dye concentration were chosen for UV sensor design due to their high total color difference. These photochromic nanofibers served as UV indicators, and a grayscale‐ adapted scale was used for evaluation. A UV sensor prototype capable of accurately determining UV exposure levels was successfully developed using photochromic nanofibers. This spectrally selective UV sensor can offer remarkable potential in managing the impact of UVR in our day‐to‐ day life.Highlights: Bead‐free, uniform nanofibers were obtained using a DMF:DCM solvent system. The nanofibers returned to their original colorless state in 5 min. The photochromic nanofibers showed high fatigue resistance. The nanofiber color indicated the UV intensity by comparing via adapted grayscale.

The aim of this study is to develop nanofibrous CO₂ adsorbents by using of textile wastes as precursor materials. Therefore, polyacrylonitrile (PAN) and PAN/cell nanofibers were produced from acrylic textile wastes. Nanofibrous membranes were subjected to stabilization, carbonization, and chemical activation processes, respectively, to produce activated carbon nanofiber (ACnF) structures. Elemental analysis, scanning electron microscope, FTIR, and Braunauer, Emmett, and Teller analyses were carried out and CO₂ adsorption performance was tested. It was observed that all samples, except PAN/cell nanofibers carbonized at 900°C, preserved their nanofibrous structure. PAN ACnFs had a lower surface area; on the other hand, they were shown to have higher carbon dioxide adsorption values compared with PAN/cell ACnFs. Reasonable adsorption capacities as high as 3.53 and 2.99 mmol/g (at 298 K at a relative pressure of 0.989) were achieved by PAN and PAN/cell ACnFs, respectively. As a result, it was investigated that sustainable ACnF‐based carbon dioxide adsorbents could be produced by the thermochemical processing of electrospun nanofibers obtained from textile wastes.

In this study, to combine the biological properties of lanolin and the advantages of electrospun nanofiber mats for developing a potent topical wound dressing/nursing pads that includes lanolin, lanolin incorporated electrospun cellulose acetate (CA), polyethylene oxide (PEO), polyethylene oxide/chitosan (PEO/chitosan) and thermoplastic polyurethane (TPU) nanofibers were developed and characterized. Surface tension, viscosity and conductivity measurements of each polymer solution were carried out in order to characterize the spinning solutions. Lanolin addition did not affect the conductivity values but increase the viscosity of each spinning solution. According to the SEM images, smooth nanofiber surfaces were produced which could be appropriate for a top layer of a nursing pad. Slightly attached, thicker nanofibers could be seen from the TPU/Lanolin images. Similar to TPU nanofibers, CA nanofibers were smoother and thinner than CA/Lanolin nanofibers. Lanolin effected the uniformity of the PEO nanofibers, but it could be said that homogeneous distribution of lanolin was achieved. Characterization of these nanofiber membranes were also carried out with FTIR, DSC, swelling and weight loss analysis. Since TPU nanofibers were hydrophobic and the addition of lanolin made the nanofiber more hydrophobic, they did not show high swelling ratios. CA nanofibers swelled 610% due to their relatively hydrophilic nature and bulky structure. PEO nanofibers were totally dissolved in the water, a very thin layer remained for PEO-Chitosan/lanolin nanofibers. So, using electrospun CA and TPU nanofiber membranes for a nursing pad upper layer could be suitable. CA/lanolin nanofibers showed better hydrophilicity and swelling when compared to TPU nanofibers. On the other hand, TPU nanofibers are more elastic and durable with lower swelling.

Photochromic dyes which change their color with UV light, are water insoluble and sensitive to the environmental conditions. In order to be able to use these dyes in textile industry, the dyes are encapsulated with a polymer, and then the encapsulated photochromic dyes are applied onto the textile materials. The encapsulated photochromic dyes can show different properties according to the photochromic dye and polymer type, capsule size and the encapsulation method applied. In this study, the performance characteristics of different commercial photochromic dye capsules were investigated after the application onto cotton fabrics by pad-cure process. It was observed that the fabrics still provide UV protection at 50 + UPF level even after 10 washing cycles. The photochromic fabrics lost their color and UV protective properties at most 16% and 4%, respectively after 20 UV on-off cycles.