Stabilization and Incipient Carbonization of Electrospun Polyacrylonitrile Nanofibers Fixated on Aluminum Substrates

Storck, Jan Lukas; Tuvshinbayar, Khorolsuren; Diestelhorst, Elise; Wehlage, Daria; Brockhagen, Bennet; Wortmann, Martin; Frese, Natalie; Ehrmann, Andrea

doi:10.3390/fib8090055

Cited by 15 publications

(24 citation statements)

References 28 publications

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“…Electrospinning on an aluminum substrate, followed by stabilization and carbonization in this configuration (AL-C) or with an additional aluminum support in a sandwich configuration (AL-SW2-C), also helped to avoid a large increase in the fiber diameter. This confirms the previously [25][26][27] suggested solution for the production of relatively straight carbon nanofibers electrospun and heat-treated on aluminum substrates.…”

Section: Resultssupporting

confidence: 90%

“…The following spinning parameters were chosen: voltage 80 kV, resulting current 0.1 mA, nozzle diameter 0.9 mm, electrode-substrate distance 240 mm, carriage speed 100 mm/s, substrate speed 0 mm/min, relative humidity 32%, and temperature in the spinning chamber 22 • C. The spinning duration was chosen as 30 min. Spinning and solution parameters were identical to those applied in previous studies [26,27].…”

Section: Methodsmentioning

confidence: 99%

“…However, these approaches may lead to macroscopic fractures in the nanofiber mats due to the uneven force distribution. This is why previous studies focused on the possibility of stabilizing PAN nanofiber mats, electrospun onto aluminum foils or other substrates, which offer mechanical support during the first stages of heat treatment [25][26][27]. It was found that while stabilizing on a substrate could indeed partially prevent the nanofibers from undesired morphological changes, most substrate parameters did not significantly influence the resulting nanofibers.…”

Section: Introductionmentioning

confidence: 99%

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Metallic Supports Accelerate Carbonization and Improve Morphological Stability of Polyacrylonitrile Nanofibers during Heat Treatment

et al. 2021

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Electrospun poly(acrylonitrile) (PAN) nanofibers are typical precursors of carbon nanofibers. During stabilization and carbonization, however, the morphology of pristine PAN nanofibers is not retained if the as-spun nanofiber mats are treated without an external mechanical force, since internal stress tends to relax, causing the whole mats to shrink significantly, while the individual fibers thicken and curl. Stretching the nanofiber mats during thermal treatment, in contrast, can result in fractures due to inhomogeneous stress. Previous studies have shown that stabilization and carbonization of PAN nanofibers electrospun on an aluminum substrate are efficient methods to retain the fiber mat dimensions without macroscopic cracks during heat treatment. In this work, we studied different procedures of mechanical fixation via metallic substrates during thermal treatment. The influence of the metallic substrate material as well as different methods of double-sided covering of the fibers, i.e. sandwiching, were investigated. The results revealed that sandwich configurations with double-sided metallic supports not only facilitate optimal preservation of the original fiber morphology but also significantly accelerate the carbonization process. It was found that unlike regularly carbonized nanofibers, the metal supports allow complete deoxygenation at low treatment temperature and that the obtained carbon nanofibers exhibit increased crystallinity.

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Section: Resultssupporting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Metallic Supports Accelerate Carbonization and Improve Morphological Stability of Polyacrylonitrile Nanofibers during Heat Treatment

et al. 2021

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“…To avoid this problem, we showed in previous studies that electrospinning on an aluminum foil and stabilizing without previously detaching the nanofiber mat from the metal foil can be used as a simple method to retain the nanofiber morphology during stabilization [26]. These first results were extended to investigations of stabilization and incipient carbonization on different aluminum foils, applying a broad range of process parameters, showing that the substrate thickness or surface did not influence the stabilization and carbonization results, while the stabilization heating rates had a significant impact on the stabilized and carbonized nanofibers [27].…”

Section: Introductionmentioning

confidence: 93%

Stabilization and Carbonization of PAN Nanofiber Mats Electrospun on Metal Substrates

Storck

Brockhagen

Sabantina

et al. 2021

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Polyacrylonitrile (PAN) nanofiber mats are typical precursors for carbon nanofibers. They can be fixed or even elongated during stabilization and subsequent carbonization to gain straight, mechanically robust carbon nanofibers. These processes necessitate additional equipment or are—if the nanofiber mats are just fixed at the edges—prone to resulting in the specimens breaking, due to an uneven force distribution. Hence, we showed in a previous study that electrospinning PAN on aluminum foils and stabilizing them fixed on these substrates, is a suitable solution to keep the desired morphology after stabilization and incipient carbonization. Here, we report on the influence of different metallic and semiconductor substrates on the physical and chemical properties of the nanofiber mats after stabilization and carbonization at temperatures up to 1200 °C. For stabilization on a metal substrate, an optimum stabilization temperature of slightly above 240 °C was found, approached with a heating rate of 0.25 K/min. Independent from the substrate material, SEM images revealed less defect fibers in the nanofiber mats stabilized and incipiently carbonized on a metal foil. Finally, high-temperature carbonization on different substrates is shown to allow for producing metal/carbon nano-composites.

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“…The carbonization process is usually carried out in an inert gas, argon or nitrogen. Carbonization is a complex process in which dehydrogenation, condensation, hydrogen transfer and isomerization take place simultaneously [36]. The final pyrolysis temperature applied controls the degree of carbonization and the residual content of foreign elements, for example, after carbonization.…”

Section: Introductionmentioning

confidence: 99%

Investigation of metallic nanoparticle distribution in PAN/magnetic nanocomposites fabricated with needleless electrospinning technique

Trabelsi

Mamun

Klöcker

et al. 2021

cdatp

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Needleless electrospinning can be used to produce polyacrylonitrile nanofibres, for example, to which magnetic nanoparticles can additionally be added. Such composite nanofibres can then be stabilised and carbonised to produce carbon composite nanofibres. The magnetic nanoparticles have an influence not only on the structure but also on the mechanical and electrical properties of the finished carbon nanofibres, as does the heat treatment during stabilisation and incipient carbonisationThe present study reports on the fabrication, heat treatment and resulting properties of poly(acrylonitrile) (PAN)/magnetic nanofibre mats prepared by needleless electrospinning from polymer solutions. A variety of microscopic and thermal characterisation methods were used to investigate in detail the chemical and morphological transition during oxidative stabilisation (280 °C) and incipient carbonisation (500 °C). PAN and nanoparticles were analysed during all stages of heat treatment. Compared to pure PAN nanofibres, the PAN/ magnetic nanofibers showed larger fiber diameters and the presence of beads and agglomerations. In this study, magnetic nanofibers were investigated in more detail with the aim of detecting undesired agglomerations. Visual observation, for example with CLSM or SEM, does not provide conclusive evidence of agglomerations in the nanofibers. But based on the capabilities of SEM/EDS many different types of samples can be easily analysed where other analytical techniques simply cannot give the fast answer.

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Stabilization and Incipient Carbonization of Electrospun Polyacrylonitrile Nanofibers Fixated on Aluminum Substrates

Cited by 15 publications

References 28 publications

Metallic Supports Accelerate Carbonization and Improve Morphological Stability of Polyacrylonitrile Nanofibers during Heat Treatment

Metallic Supports Accelerate Carbonization and Improve Morphological Stability of Polyacrylonitrile Nanofibers during Heat Treatment

Stabilization and Carbonization of PAN Nanofiber Mats Electrospun on Metal Substrates

Investigation of metallic nanoparticle distribution in PAN/magnetic nanocomposites fabricated with needleless electrospinning technique

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