Research

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10 pages, 3136 KiB

Open AccessArticle

Research on the Morphology Reconstruction of Deep Cryogenic Treatment on PtRu/nitrogen-Doped Graphene Composite Carbon Nanofibers

by Shuaishuai Lv, Yangyang Zhu, Xingxing Wang, Yu Zhu, Kaixuan Wang, Hongjun Ni and Ruobo Gu

Materials 2022, 15(3), 908; https://doi.org/10.3390/ma15030908 - 25 Jan 2022

Viewed by 1864

Abstract

To improve the performance of PtRu/nitrogen-doped graphene composite carbon nanofibers, the composite carbon nanofibers were thermally compensated by deep cryogenic treatment (DCT), which realized the morphology reconstruction of composite carbon nanofibers. The effects of different DCT times were compared: 12 h, 18 h, [...] Read more.

To improve the performance of PtRu/nitrogen-doped graphene composite carbon nanofibers, the composite carbon nanofibers were thermally compensated by deep cryogenic treatment (DCT), which realized the morphology reconstruction of composite carbon nanofibers. The effects of different DCT times were compared: 12 h, 18 h, and 24 h. The morphology reconstruction mechanism was explored by combining the change of inner chain structure and material group. The results showed that the fibers treated for 12 h had better physical and chemical properties, where the diameter is evenly distributed between 500 and 800 nm. Combined with Fourier infrared analysis, the longer the cryogenic time, the more easily the water vapor and nitrogen enter polymerization reaction, causing changes of chain structure and degradation performance. With great performance of carbonization and group transformation, the PtRu/nitrogen-doped graphene composite carbon nanofibers can be used as an efficient direct alcohol fuel cell catalyst and promote its commercialization. Full article

(This article belongs to the Special Issue Electrospinning: Nanofabrication and Application)

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13 pages, 2479 KiB

Open AccessArticle

A Facile Design of Colourimetric Polyurethane Nanofibrous Sensor Containing Natural Indicator Dye for Detecting Ammonia Vapour

by Ayben Pakolpakçıl and Zbigniew Draczyński

Materials 2021, 14(22), 6949; https://doi.org/10.3390/ma14226949 - 17 Nov 2021

Cited by 8 | Viewed by 1922

Abstract

Chemicals and industrial gases endanger both human health and the environment. The inhalation of colourless ammonia gas (NH₃) can cause organ damage or even death in humans. Colourimetric materials are becoming more popular in the search for smart textiles for both [...] Read more.

Chemicals and industrial gases endanger both human health and the environment. The inhalation of colourless ammonia gas (NH₃) can cause organ damage or even death in humans. Colourimetric materials are becoming more popular in the search for smart textiles for both fashion and specific occupational applications. Colourimetric textile sensors based on indicator dyes could be very useful for detecting strong gaseous conditions and monitoring gas leaks. In this study, black carrot extract (BCE) as a natural indicator dye and polyurethane (PU) polymer were used to develop a colourimetric sensor by electrospinning. The properties of the BCE/PU nanofibrous mats were characterized by the Fourier transform infrared spectrum (FTIR) and a scanning electron microscope (SEM). The BCE caused a change in the morphology of the PU nanofibrous mat. To evaluate the colour shift due to NH₃ vapour, the BCE/PU nanofibrous mats were photographed by a camera, and software was used to obtain the quantitative colour data (CIE L*a*b). The BCE/PU nanofibrous exhibited a remarkable colour change from pink–red to green–blue under NH₃ vapour conditions with a fast response time (≤30 s). These findings showed that colourimetric nanofibrous textile sensors could be a promising in situ material in protective clothing that changes colour when exposed to harmful gases. Full article

(This article belongs to the Special Issue Electrospinning: Nanofabrication and Application)

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13 pages, 8230 KiB

Open AccessArticle

The Possibility of Reuse of Nanofiber Mats by Machine Washing at Different Temperatures

by Al Mamun, Imane Moulefera, Yusuf Topuz, Marah Trabelsi and Lilia Sabantina

Materials 2021, 14(17), 4788; https://doi.org/10.3390/ma14174788 - 24 Aug 2021

Cited by 3 | Viewed by 1889

Abstract

The worldwide spread of coronavirus COVID-19 infections demonstrates the great need for personal protective equipment and, in particular, hygiene masks. These masks are essential for the primary protection of the respiratory tract against pathogens such as viruses and bacteria that are infectious and [...] Read more.

The worldwide spread of coronavirus COVID-19 infections demonstrates the great need for personal protective equipment and, in particular, hygiene masks. These masks are essential for the primary protection of the respiratory tract against pathogens such as viruses and bacteria that are infectious and transmitted through the air as large droplets or via small airborne particles. The use of protective masks will continue to accompany humans for an indefinite period of time, and therefore there is an urgent need for a safe method to extend their usability by reusing them under perspective with minimal loss of protective properties. Nanofiber mats are widely used in masks and in this study the reusability of nanofiber mats is investigated by washing them at different temperatures. This paper shows the first measurements of the washability of nanofiber mats. Furthermore, the air permeability is measured, and the evaporation resistance is evaluated. According to the results of this study, the air permeability performance of nanofiber mats does not change significantly after washing, confirming the possibility of reuse. Full article

(This article belongs to the Special Issue Electrospinning: Nanofabrication and Application)

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9 pages, 2965 KiB

Open AccessCommunication

Preparation and Performance of PAN–PAC Nanofibers by Electrospinning Process to Remove NOM from Water

by Beata Malczewska

Materials 2021, 14(16), 4426; https://doi.org/10.3390/ma14164426 - 07 Aug 2021

Cited by 3 | Viewed by 1689

Abstract

The technology based on electrospun membranes exhibits great potential in water treatment. This study presents experimental data involving the fabrication of nanofiber membranes with powdered activated carbon (PAC) and its application for the removal of natural organic matter. The fabricated membrane materials were [...] Read more.

The technology based on electrospun membranes exhibits great potential in water treatment. This study presents experimental data involving the fabrication of nanofiber membranes with powdered activated carbon (PAC) and its application for the removal of natural organic matter. The fabricated membrane materials were characterized using various techniques. These include scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction analysis. The incorporation of PAC nanoparticles influences the structure and physicochemical properties as well as the transport and separation characteristics of the produced membranes. The applicability of the fabricated carbon-based membrane was tested in the filtration experiments. The fabricated membrane is characterized by a high NOM removal efficiency of 79% in the filtration process. Further modification of the membrane composition may result in a further increase in the efficiency of removing contaminants from water. Full article

(This article belongs to the Special Issue Electrospinning: Nanofabrication and Application)

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14 pages, 5207 KiB

Open AccessCommunication

Orientation of Electrospun Magnetic Nanofibers Near Conductive Areas

by Jan Lukas Storck, Timo Grothe, Al Mamun, Lilia Sabantina, Michaela Klöcker, Tomasz Blachowicz and Andrea Ehrmann

Materials 2020, 13(1), 47; https://doi.org/10.3390/ma13010047 - 20 Dec 2019

Cited by 29 | Viewed by 3332

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Electrospinning: Nanofabrication and Application)

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12 pages, 6283 KiB

Open AccessFeature PaperArticle

Surface-Modified Nanofibrous PVDF Membranes for Liquid Separation Technology

by Evren Boyraz, Fatma Yalcinkaya, Jakub Hruza and Jiri Maryska

Materials 2019, 12(17), 2702; https://doi.org/10.3390/ma12172702 - 23 Aug 2019

Cited by 25 | Viewed by 3655

Abstract

Preparing easily scaled up, cost-effective, and recyclable membranes for separation technology is challenging. In the present study, a unique and new type of modified polyvinylidene fluoride (PVDF) nanofibrous membrane was prepared for the separation of oil–water emulsions. Surface modification was done in two [...] Read more.

Preparing easily scaled up, cost-effective, and recyclable membranes for separation technology is challenging. In the present study, a unique and new type of modified polyvinylidene fluoride (PVDF) nanofibrous membrane was prepared for the separation of oil–water emulsions. Surface modification was done in two steps. In the first step, dehydrofluorination of PVDF membranes was done using an alkaline solution. After the first step, oil removal and permeability of the membranes were dramatically improved. In the second step, TiO₂ nanoparticles were grafted onto the surface of the membranes. After adding TiO₂ nanoparticles, membranes exhibited outstanding anti-fouling and self-cleaning performance. The as-prepared membranes can be of great use in new green separation technology and have great potential to deal with the separation of oil–water emulsions in the near future. Full article

(This article belongs to the Special Issue Electrospinning: Nanofabrication and Application)

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Review

Jump to: Research

24 pages, 1671 KiB

Open AccessReview

Electrospun Alginate Nanofibers Toward Various Applications: A Review

by Teboho Clement Mokhena, Mokgaotsa Jonas Mochane, Asanda Mtibe, Maya Jacob John, Emmanuel Rotimi Sadiku and Jeremia Shale Sefadi

Materials 2020, 13(4), 934; https://doi.org/10.3390/ma13040934 - 20 Feb 2020

Cited by 61 | Viewed by 5272

Abstract

Alginate has been a material of choice for a spectrum of applications, ranging from metal adsorption to wound dressing. Electrospinning has added a new dimension to polymeric materials, including alginate, which can be processed to their nanosize levels in order to afford unique [...] Read more.

Alginate has been a material of choice for a spectrum of applications, ranging from metal adsorption to wound dressing. Electrospinning has added a new dimension to polymeric materials, including alginate, which can be processed to their nanosize levels in order to afford unique nanostructured materials with fascinating properties. The resulting nanostructured materials often feature high porosity, stability, permeability, and a large surface-to-volume ratio. In the present review, recent trends on electrospun alginate nanofibers from over the past 10 years toward advanced applications are discussed. The application of electrospun alginate nanofibers in various fields such as bioremediation, scaffolds for skin tissue engineering, drug delivery, and sensors are also elucidated. Full article

(This article belongs to the Special Issue Electrospinning: Nanofabrication and Application)

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14 pages, 2005 KiB

Open AccessReview

A Review on Membrane Technology and Chemical Surface Modification for the Oily Wastewater Treatment

by Fatma Yalcinkaya, Evren Boyraz, Jiri Maryska and Klara Kucerova

Materials 2020, 13(2), 493; https://doi.org/10.3390/ma13020493 - 20 Jan 2020

Cited by 129 | Viewed by 9906

Abstract

Cleaning of wastewater for the environment is an emerging issue for the living organism. The separation of oily wastewater, especially emulsified mixtures, is quite challenged due to a large amount of wastewater produced in daily life. In this review, the membrane technology for [...] Read more.

Cleaning of wastewater for the environment is an emerging issue for the living organism. The separation of oily wastewater, especially emulsified mixtures, is quite challenged due to a large amount of wastewater produced in daily life. In this review, the membrane technology for oily wastewater treatment is presented. In the first part, the global membrane market, the oil spill accidents and their results are discussed. In the second and third parts, the source of oily wastewater and conventional treatment methods are represented. Among all methods, membrane technology is considered the most efficient method in terms of high separation performance and easy to operation process. In the fourth part, we provide an overview of membrane technology, fouling problem, and how to improve the self-cleaning surface using functional groups for effectively treating oily wastewater. The recent development of surface-modified membranes for oily wastewater separation is investigated. It is believed that this review will promote understanding of membrane technology and the development of surface modification strategies for anti-fouling membranes. Full article

(This article belongs to the Special Issue Electrospinning: Nanofabrication and Application)

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17 pages, 6602 KiB

Open AccessFeature PaperReview

Conductive Electrospun Nanofiber Mats

by Tomasz Blachowicz and Andrea Ehrmann

Materials 2020, 13(1), 152; https://doi.org/10.3390/ma13010152 - 31 Dec 2019

Cited by 45 | Viewed by 7688

Abstract

Conductive nanofiber mats can be used in a broad variety of applications, such as electromagnetic shielding, sensors, multifunctional textile surfaces, organic photovoltaics, or biomedicine. While nanofibers or nanofiber from pure or blended polymers can in many cases unambiguously be prepared by electrospinning, creating [...] Read more.

Conductive nanofiber mats can be used in a broad variety of applications, such as electromagnetic shielding, sensors, multifunctional textile surfaces, organic photovoltaics, or biomedicine. While nanofibers or nanofiber from pure or blended polymers can in many cases unambiguously be prepared by electrospinning, creating conductive nanofibers is often more challenging. Integration of conductive nano-fillers often needs a calcination step to evaporate the non-conductive polymer matrix which is necessary for the electrospinning process, while conductive polymers have often relatively low molecular weights and are hard to dissolve in common solvents, both factors impeding spinning them solely and making a spinning agent necessary. On the other hand, conductive coatings may disturb the desired porous structure and possibly cause problems with biocompatibility or other necessary properties of the original nanofiber mats. Here we give an overview of the most recent developments in the growing field of conductive electrospun nanofiber mats, based on electrospinning blends of spinning agents with conductive polymers or nanoparticles, alternatively applying conductive coatings, and the possible applications of such conductive electrospun nanofiber mats. Full article

(This article belongs to the Special Issue Electrospinning: Nanofabrication and Application)

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