Research

21 pages, 4805 KiB

Open AccessEditor’s ChoiceArticle

Conducting Electrospun Nanofibres: Monitoring of Iodine Doping of P3HT through Infrared (IRAV) and Raman (RaAV) Polaron Spectroscopic Features

by Alessia Arrigoni, Luigi Brambilla, Chiara Castiglioni and Chiara Bertarelli

Nanomaterials 2022, 12(23), 4308; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12234308 - 04 Dec 2022

Cited by 2 | Viewed by 1688

Abstract

Aligned polymer nanofibres are prepared by means of the electrospinning of a chlorobenzene solution containing regioregular poly(3-hexyltiophene-2,5-diyl), P3HT, and poly(ethylene oxide), PEO. The PEO scaffold is easily dissolved with acetonitrile, leaving pure P3HT fibres, which do not show structural modification. Polymer fibres, either [...] Read more.

Aligned polymer nanofibres are prepared by means of the electrospinning of a chlorobenzene solution containing regioregular poly(3-hexyltiophene-2,5-diyl), P3HT, and poly(ethylene oxide), PEO. The PEO scaffold is easily dissolved with acetonitrile, leaving pure P3HT fibres, which do not show structural modification. Polymer fibres, either with or without the PEO supporting polymer, are effectively doped by exposure to iodine vapours. Doping is monitored following the changes in the doping-induced vibrational bands (IRAVs) observed in the infrared spectra and by means of Raman spectroscopy. Molecular orientation inside the fibres has been assessed by means of IR experiments in polarised light, clearly demonstrating that electrospinning induces the orientation of the polymer chains along the fibre axis as well as of the defects introduced by doping. This work illustrates a case study that contributes to the fundamental knowledge of the vibrational properties of the doping-induced defects—charged polarons—of P3HT. Moreover, it provides experimental protocols for a thorough spectroscopic characterisation of the P3HT nanofibres, and of doped conjugated polymers in general, opening the way for the control of the material structure when the doped polymer is confined in a one-dimensional architecture. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Application of Nanofibers)

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16 pages, 5567 KiB

Open AccessArticle

Breaking and Connecting: Highly Hazy and Transparent Regenerated Networked-Nanofibrous Cellulose Films via Combination of Hydrolysis and Crosslinking

by Jamaliah Aburabie and Raed Hashaikeh

Nanomaterials 2022, 12(15), 2729; https://doi.org/10.3390/nano12152729 - 08 Aug 2022

Cited by 7 | Viewed by 1719

Abstract

High optical transparency combined with high optical haze are essential requirements for optoelectronic substrates. Light scattering caused by haze is responsible for increasing light harvesting in photon-absorbing active materials, hence increasing efficiencies. A trade-off between transparency and haze is common in solar substrates [...] Read more.

High optical transparency combined with high optical haze are essential requirements for optoelectronic substrates. Light scattering caused by haze is responsible for increasing light harvesting in photon-absorbing active materials, hence increasing efficiencies. A trade-off between transparency and haze is common in solar substrates with high transparency (~90%) and low optical haze (~20%), or vice versa. In this study, we report a novel, highly transparent film fabricated from regenerated cellulose after controlled acid-hydrolysis of microcrystalline cellulose (MCC). The developed networked-nanofibrous cellulose was chemically crosslinked with glutaraldehyde (GA) and vacuum-cured to facilitate the fabrication of mechanically stable films. The effects of crosslinker concentration, crosslinking time, and curing temperature were investigated. Optimum conditions for fabrication unveils high optical transparency (~94%) and high haze (~60%), using 25% GA for 24 hr with a curing temperature of 25 °C; therefore, conveying an optimal substrate for optoelectronics applications. The high haze arises primarily from the crystalline, networked crystals of cellulose II structure formed within the regenerated cellulose upon hydrolysis. Moreover, the developed crosslinked film presents high thermal stability, water resistance, and good mechanical resilience. This high-performance crosslinked cellulose film can be considered a potential material for new environmentally-friendly optical substrates. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Application of Nanofibers)

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13 pages, 5529 KiB

Open AccessArticle

Spectroscopy and Cyclic Voltammetry Properties of SPEEK/CuO Nanocomposite at Screen-Printed Gold Electrodes

by Omolola E. Fayemi, Onkarabile G. Pooe, Funmilola A. Adesanya and Ikechukwu P. Ejidike

Nanomaterials 2022, 12(11), 1825; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12111825 - 26 May 2022

Cited by 4 | Viewed by 2027

Abstract

A successful electrochemical study of copper oxide nanoparticles (CuO NPs), sulfonated poly (ether ether ketone) polymer (SPEEK), and sulfonated polyether ether ketone-copper oxide (SPEEK/CuO) nanocomposite on bare gold electrodes was conducted. The synthesized CuO NPs and SPEEK/CuO nanocomposite were characterized using X-ray diffraction [...] Read more.

A successful electrochemical study of copper oxide nanoparticles (CuO NPs), sulfonated poly (ether ether ketone) polymer (SPEEK), and sulfonated polyether ether ketone-copper oxide (SPEEK/CuO) nanocomposite on bare gold electrodes was conducted. The synthesized CuO NPs and SPEEK/CuO nanocomposite were characterized using X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and electron dispersive spectroscopy (EDS). The XRD showed that the diameter of the CuO NPs synthesized was 20.44 nm. The cyclic voltammetry properties of bare screen-print gold, SPEEK and SPEEK/CuO-modified electrodes were assessed in a 5 mM K₃[Fe(CN)₆] solution. The electrochemical performance of the fabricated electrodes investigated revealed that CuO NPs improved the electrochemical properties of SPEEK, and the quantum size effect indicated good adsorption by the SPEEK/CuO nanocomposite compared to the SPEEK polymer and the CuO NPs alone. Moreover, the Tafel values indicated the enhanced electrochemical performance of the other electrodes as compared with the SPEEK/CuO nanocomposite. This, therefore, confirmed the successful incorporation of CuO NPs into the SPEEK polymer, as the increased surface area and the interactions between the polymer matrix and CuO fillers improved the electrochemical performance of the electrode. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Application of Nanofibers)

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14 pages, 2986 KiB

Open AccessArticle

Interaction of Mg Alloy with PLA Electrospun Nanofibers Coating in Understanding Changes of Corrosion, Wettability, and pH

by Manuela Elena Voicu, Ioana Demetrescu, Andrei Dorobantu, Marius Enachescu, George-Octavian Buica and Daniela Ionita

Nanomaterials 2022, 12(8), 1369; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12081369 - 16 Apr 2022

Cited by 9 | Viewed by 1949

Abstract

A modified biodegradable magnesium alloy (AZ31, 96 wt% Mg, 3 wt% Al, and 1 wt% Zn) with polylactic acid (PLA) nanofibers was obtained by the electrospinning technique. The presence of PLA nanofibers was evidenced using Fourier transform infrared spectroscopy (FT-IR) and using an [...] Read more.

A modified biodegradable magnesium alloy (AZ31, 96 wt% Mg, 3 wt% Al, and 1 wt% Zn) with polylactic acid (PLA) nanofibers was obtained by the electrospinning technique. The presence of PLA nanofibers was evidenced using Fourier transform infrared spectroscopy (FT-IR) and using an scanning electronic microscope (SEM) equipped with an energy dispersive X-ray spectroscopy (EDX) module. The degradation behavior of an uncoated Mg alloy and a Mg alloy coated with PLA was evaluated through hydrogen evolution, pH, and electrochemical measurements in simulated body fluid. Contact angle measurements showed a shift from hydrophilic towards the hydrophobic character of the alloy after its coating with PLA nanofibers. Furthermore, the electrochemical measurement results show that the Mg based alloy coated with PLA inhibits hydrogen evolution, thus being less prone to degradation. The aim of this research is not only to reduce the corrosion rate of Mg alloy and to improve its properties with the help of polylactic acid coating, but also to provide a study to understand the hydrophilic–hydrophobic balance of biodegradable magnesium based on surface energy investigations. Taking into account corrosion rate, wettability, and pH changes, an empiric model of the interaction of Mg alloy with PLA nanofibers is proposed. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Application of Nanofibers)

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11 pages, 30717 KiB

Open AccessArticle

Scaled-Up Multi-Needle Electrospinning Process Using Parallel Plate Auxiliary Electrodes

by Étienne J. Beaudoin, Maurício M. Kubaski, Mazen Samara, Ricardo J. Zednik and Nicole R. Demarquette

Nanomaterials 2022, 12(8), 1356; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12081356 - 15 Apr 2022

Cited by 12 | Viewed by 2485

Abstract

Electrospinning has gained much attention in recent years due to its ability to easily produce high-quality polymeric nanofibers. However, electrospinning suffers from limited production capacity and a method to readily scale up this process is needed. One obvious approach includes the use of [...] Read more.

Electrospinning has gained much attention in recent years due to its ability to easily produce high-quality polymeric nanofibers. However, electrospinning suffers from limited production capacity and a method to readily scale up this process is needed. One obvious approach includes the use of multiple electrospinning needles operating in parallel. Nonetheless, such an implementation has remained elusive, partly due to the uneven electric field distribution resulting from the Coulombic repulsion between the charged jets and needles. In this work, the uniformization of the electric field was performed for a linear array of twenty electrospinning needles using lateral charged plates as auxiliary electrodes. The effect of the auxiliary electrodes was characterized by investigating the semi-vertical angle of the spun jets, the deposition area and diameter of the fibers, as well as the thickness of the produced membranes. Finite element simulation was also used to analyze the impact of the auxiliary electrodes on the electric field intensity below each needle. Implementing parallel lateral plates as auxiliary electrodes was shown to help achieve uniformization of the electric field, the semi-vertical angle of the spun jet, and the deposition area of the fibers for the multi-needle electrospinning process. The high-quality morphology of the polymer nanofibers obtained by this improved process was confirmed by scanning electron microscopy (SEM). These findings help resolve one of the primary challenges that have plagued the large-scale industrial adoption of this exciting polymer processing technique. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Application of Nanofibers)

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9 pages, 5099 KiB

Open AccessArticle

Ultra-High T_g Thermoset Fibers Obtained by Electrospinning of Functional Polynorbornenes

by Basile Commarieu, Moubarak Compaoré, Raphaël de Boëver, Régis Imbeault, Maxime Leprince, Barbara Martin, Bruno Perard, Weiguang Qiu and Jerome P. Claverie

Nanomaterials 2022, 12(6), 967; https://0-doi-org.brum.beds.ac.uk/10.3390/nano12060967 - 15 Mar 2022

Viewed by 1861

Abstract

Insertion polynorbornenes (PBNEs) are rigid-rod polymers that have very high glass transition temperatures (T_g). In this study, two functional PNBEs were electrospun in the presence of a variety of cross-linkers, resulting in fibers with T_gs greater than 300 °C. [...] Read more.

Insertion polynorbornenes (PBNEs) are rigid-rod polymers that have very high glass transition temperatures (T_g). In this study, two functional PNBEs were electrospun in the presence of a variety of cross-linkers, resulting in fibers with T_gs greater than 300 °C. The fibers are long (several mm), rigid, and with diameters that can be tuned in the range 300 nm–10 μm. The electrospinning process can be used to encapsulate dyes or graphene dots. Due to the high cross-linking density of the fiber, dye leaching is prevented. In contrast with other rigid-rod polymers, electrospinning of PNBE is facile and can be performed at injection rates as high as 1 mL/min. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Application of Nanofibers)

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16 pages, 7701 KiB

Open AccessArticle

Study on the Preparation and Lipophilic Properties of Polyvinyl Alcohol (PVA) Nanofiber Membranes via Green Electrospinning

by Jun Cong Ge, Guirong Wu, Sam Ki Yoon, Min Soo Kim and Nag Jung Choi

Nanomaterials 2021, 11(10), 2514; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11102514 - 27 Sep 2021

Cited by 30 | Viewed by 3804

Abstract

As an environmentally friendly water-soluble polymer, polyvinyl alcohol (PVA) has attracted extensive attention because of its non-toxic, degradable, low cost, and good biocompatibility. Electrospinning is a kind of nanotechnology, and the nanofiber membrane prepared by it has the advantages of large surface area-to-volume [...] Read more.

As an environmentally friendly water-soluble polymer, polyvinyl alcohol (PVA) has attracted extensive attention because of its non-toxic, degradable, low cost, and good biocompatibility. Electrospinning is a kind of nanotechnology, and the nanofiber membrane prepared by it has the advantages of large surface area-to-volume ratios, nano- to micron-sized fibers, etc. Herein, a simple and facile one-step green electrospinning method was developed to fabricate various environmentally friendly PVA nanofiber membranes. The lipophilic properties of PVA membranes were investigated and optimized according different PVA concentrations. The PVA electrospun fiber prepared from the solution at a concentration of 10 wt% had the highest adsorption capacity for the adsorption of new and waste engine oils, and the waste engine oil adsorption capacity (12.70 g/g) was higher than that of new engine oil (11.67 g/g). It also has a relatively large BET surface area (12.05 m²/g), a pore volume (0.04 cm³/g), and an appropriate pore diameter (13.69 nm) and fiber diameter (174.21 nm). All electrospun PVA membranes showed excellent lipophilic properties due to their oil contact angles of much less than 30°. Therefore, PVA electrospun fibrous membranes have great application potential in the field of purifying engine oil due to the excellent lipophilic properties and oil absorption capacity. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Application of Nanofibers)

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13 pages, 3930 KiB

Open AccessArticle

Electrospun Nanofiber-Based Viroblock/ZnO/PAN Hybrid Antiviral Nanocomposite for Personal Protective Applications

by Abdul Salam, Tufail Hassan, Tooba Jabri, Shagufta Riaz, Amina Khan, Kanwal Muhammad Iqbal, Saif ullah Khan, Muhammad Wasim, Muhammad Raza Shah, Muhammad Qamar Khan and Ick-Soo Kim

Nanomaterials 2021, 11(9), 2208; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11092208 - 27 Aug 2021

Cited by 23 | Viewed by 3219

Abstract

Designing novel antiviral personal protective equipment (PPE) is crucial for preventing viral infections such as COVID-19 in humans. Here, we fabricate an electrospun nanofiber-based Viroblock (VB)-loaded polyacrylonitrile (PAN)/zinc oxide (ZnO) hybrid nanocomposite for PPE applications. Five different concentrations of Viroblock (0.5%, 1.5%, 2.5%, [...] Read more.

Designing novel antiviral personal protective equipment (PPE) is crucial for preventing viral infections such as COVID-19 in humans. Here, we fabricate an electrospun nanofiber-based Viroblock (VB)-loaded polyacrylonitrile (PAN)/zinc oxide (ZnO) hybrid nanocomposite for PPE applications. Five different concentrations of Viroblock (0.5%, 1.5%, 2.5%, 3.5%, and 5%) were added to PAN/ZnO solution and loaded for electrospinning. The developed samples reflected antibacterial activity of 92.59% and 88.64% against Staphylococcus aureus and Pseudomonas aeruginosa bacteria, respectively, with 5% VB loading. Moreover, a significant reduction in virus titer (37%) was observed with the 5% VB/PAN/ZnO nanofiber sheet. Hence, VB-loaded PAN/ZnO nanofibers have great potential to kill enveloped viruses such as influenzas and coronaviruses and could be the ideal candidate for the development of nanofiber-based PPE, such as facemasks and surgical gowns, which can play a key role in the protection of frontline health workers and the general public in the COVID-19 pandemic. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Application of Nanofibers)

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