Electrospinning Functional Polyacrylonitrile Nanofibers with Polyaniline, Carbon Nanotubes, and Silver Nitrate as Additives

Electrospinning of composite nanofibers has been attracting great attention as a way of producing functional nanofibers. Composite nanofibers are produced with the incorporation of the additives into the polymer melt/solution before electrospinning process and reported to show many superior properties such as high modulus, increased strength, improved thermal stability, or some new functionalities such as flame retardancy, antimicrobial properties, water repellency, soil resistance, decreased gas permeability, electromagnetic shielding, electrical conductivity, and so on. The availability of the wide range of additives makes it possible to produce a wide range of functional nanocomposite nanofibers that are promising for various applications. Polyaniline (PANI) as an inherently conductive polymer is being investigated as an additive for improving conductivity. Carbon nanotubes (CNT) are widely used for either their reinforcement ability or their superior electrical conductivity. Silver nanoparticles (AgNPs) are being incorporated into polymer matrices to obtain antibacterial activity. This chapter provides a comprehensive review about polyacrylonitrile (PAN) nanofibers with PANI, CNTs, AgNPs, and their combinations and highlights the synergistic effects obtained by their combined use

Recent Advances in Applications of Ceramic Nanofibers

Ceramic materials are well known for their hardness, inertness, superior mechanical and thermal properties, resistance against chemical erosion and corrosion. Ceramic nanofibers were first manufactured through a combination of electrospinning with sol–gel method in 2002. The electrospun ceramic nanofibers display unprecedented properties such as high surface area, length, thermo-mechanical properties, and hierarchically porous structure which make them candidates for a wide range of applications such as tissue engineering, sensors, water remediation, energy storage, electromagnetic shielding, thermal insulation materials, etc. This chapter focuses on the most recent advances in the applications of ceramic nanofibers

Interdiffusing core-shell nanofiber interleaved composites for excellent Mode I and Mode II delamination resistance

Electrospun nanofibre interleaving has a great potential for toughening of composite laminates as an effective, safe and industrially relevant method. Although many studies showcase large increases in delamination resistance, these are typically obtained under either Mode I or Mode II loading and for a wide variety of nanofibres. Here, we present a more general approach towards simultaneous excellent Mode I and Mode II delamination resistance using a single nanofibre system without the need for additional chemical modification steps or speciality polymers. It is illustrated based on the concept of interdiffusion of polycaprolactone nanofibres during the curing process into the epoxy matrix resin for improved adhesion. The results show that for a simultaneous increase in Mode I and Mode II delamination resistance, the adhesion and the fibre morphology of the nanofibres are crucial. The methodology is then expanded to allow for industrial relevant working windows by core-shell structured polyamide/polycaprolactone nanofibres. This approach results in a of 650 ± 50 J m-2 (+ca. 60% vs. virgin material) and a of 3160 ± 35 J m-2 (+ca. 60% vs. virgin material)

Effect of differently functionalized carbon nanotubes on the properties of composite nanofibres

Effect of differently functionalized (carboxyl, amine and hydroxyl functionalized) multi-walled carbon nanotubes (MWCNTs) on the structure and properties of composite polyacrylonitrile nanofibres produced by electrospinning has been studied. Fourier transform ınfrared spectroscopy has been used to confirm the successful functionalization of carbon nanotubes while mechanical testing, electrical conductivity, scanning electron microscopy, differential scanning calorimetry and X-ray diffraction analysis have been used to characterize the composite polyacrylonitrile nanofibre webs. The addition of MWCNTs, either pristine or functionalized, results in slight increases in the diameter of nanofibres. The tensile strength, crystallinity, thermal properties are all found to be affected by the functional groups of the carbon nanotubes, while the conductivities of the nanowebs seem to be insensitive to the different functional groups of the carbon nanotubes

Pullulan Films with PCMs: Recyclable Bio-Based Films with Thermal Management Functionality

The use of phase-changing materials (PCMs) is a practical and powerful way of buffering thermal fluctuations and maintaining the isothermal nature of the storage process. In this study, melamine formaldehyde microcapsules with paraffin cores were used as PCMs; pullulan films with PCMs were prepared by the film-casting method; and the composite films prepared were analysed with regard to their chemical structure, thermal properties, thermal stability, and recyclability. Uniform films displaying thermal management functionality were prepared. The amount of 75 wt.% PCM were added to the pullulan film structure which enabled the preparation of a composite film that displayed 104.85 J g−1 of heat storage during heating and 103.58 J g−1 of heat release during cooling. Multiple heating and cooling cycles showed that the composite films maintained their thermal management functionality after multiple heating-cooling cycles. The PCMs could be recovered with a yield of approximately 95% by the application of a simple dissolution and filtration process. The morphology, chemical structure, and thermal properties of the PCMs were maintained after the recovery process. The bio-based composite films with thermal management functionality and recyclability are proposed as an innovative, practical, and effective system for thermoactive storage and packaging applications

Polyacrylonitrile/polyaniline composite nanofiber webs with electrostatic discharge properties

In this study, composite nanofibers of polyacrylonitrile (PAN) and polyaniline (PANI) were successfully produced by electrospinning technique and the effects of different dopants such as camphorsulfonic acid (CSA), dodecylbenzene sulfonic acid (DBSA) and dodecylbenzene sulfonic acid sodium salt (DBSANa(+)), and different solvents such as dimethylsulfoxide (DMSO) and N,N-dimethylformamide (DMF) on the properties of PAN/PANI composite nanofiber webs have been investigated. It has been observed that nanofibers produced from DMSO generally had larger fiber diameters and higher breaking strength than nanofibers produced from DMF. CSA could dope better than DBSA(iso) and DBSANa(+). CSA resulted in the highest conductivity when DMSO was used while it resulted in lower conductivity in DMF. The insulator PAN became a semiconductive material with the incorporation of CSA-doped PANI. The highest electrical conductivity obtained was 10(-6)S/cm which is in the range suitable for electrostatic discharge applications.In this study, composite nanofibers of polyacrylonitrile (PAN) and polyaniline (PANI) were successfully produced by electrospinning technique and the effects of different dopants such as camphorsulfonic acid (CSA), dodecylbenzene sulfonic acid (DBSA) and dodecylbenzene sulfonic acid sodium salt (DBSANa+), and different solvents such as dimethylsulfoxide (DMSO) and&nbsp;N,N&prime;-dimethylformamide (DMF) on the properties of PAN/PANI composite nanofiber webs have been investigated. It has been observed that nanofibers produced from DMSO generally had larger fiber diameters and higher breaking strength than nanofibers produced from DMF. CSA could dope better than DBSA(iso) and DBSANa+. CSA resulted in the highest conductivity when DMSO was used while it resulted in lower conductivity in DMF. The insulator PAN became a semiconductive material with the incorporation of CSA-doped PANI. The highest electrical conductivity obtained was 10&minus;6&thinsp;S/cm which is in the range suitable for electrostatic discharge applications.</p

The effect of the dissolution process and the polyaniline content on the properties of polyacrylonitrile-polyaniline composite nanoweb

There are several studies regarding polyacrylonitrile composite nanofibers with polyaniline doped with dodecylbenzene sulfonic acid and solved by N,N-dimethyl formamide which were mostly performed to analyze the thermal and morphological properties. In this study, camphor sulfonic acid-doped polyaniline and polyacrylonitrile composite nanofibers were electrospun from solutions in dimethylsulfoxide and the effect of polyaniline content and the application of different dissolution methods on the morphology, chemical structure, conductivity, crystallinity, mechanical, and thermal properties of nanowebs were investigated. Morphology, nanofiber diameters, chemical structure, crystallinity, mechanical properties, and thermal properties of the nanofibers were all affected by the polyaniline addition. Compared to the conductivity of neat polyacrylonitrile nanofibers, the conductivity of the composite nanofibers was improved, reaching a value higher than 10(-6)S/cm with 3wt% polyaniline content which was in the range for electrostatic discharge applications (10(-9) to 10(-6)S/cm). Increase in dissolution time and application of ultrasonic homogenization affected the diameter, mechanical properties, crystallinity, and thermal properties of the nanofibers, while they had negligible effects on conductivity

Synergistic effect of polyaniline, nanosilver, and carbon nanotube mixtures on the structure and properties of polyacrylonitrile composite nanofiber

In this study, various amounts of carbon nanotubes (CNTs), nanosilver (AgNPs), and polyaniline (PANI) were incorporated at the same pot into the structure of composite polyacrylonitrile (PAN) nanofibers, which were produced by electrospinning process in order to see synergistic effect of the additives on the final properties of the composite materials. Performance and characteristic properties of composite nanofibers were analyzed by tensile tester, electrical conductivity meter, Fourier Transform Infrared Spectroscopy, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and antimicrobial activity test. Statistical analysis (analysis of variance) was performed to see whether the differences were statistically significant or not. It was seen that samples with AgNPs had higher breaking strength and electrical conductivity than the samples with CNTs. Generally, PANI improved the crystallinity of the composite material more than the nanoparticles (CNTs and AgNPs). Even though each of the nanoparticles was used in low concentrations, the composite materials (PAN-1CNT-1AgNO(3)-R and PAN-PANI-1AgNO(3)-R) gained antimicrobial properties due to the synergistic effect of additives. The results suggested that PAN composite nanofibers with 3wt% PANI and 1wt% AgNO3 generally presented better performance than the other samples in terms of electrical conductivity, antimicrobial activity, mechanical strength, crystallization, and thermal stability

Polyacrylonitrile-Polyaniline Composite Nanofiber Webs: Effects of Solvents, Redoping Process and Dispersion Technique

This study was carried out to examine the effect of different solvents (DMSO, NMP, DMF) and solvent mixtures, application of dispersion and mixing techniques during solution preparation and redoping process on polyacrylonitrile (PAN) and camphorsulfonic acid (CSA) doped polyaniline (PANT) composite nanofibers. It was observed that nanofibers produced from DMSO and NMP solvents had larger fiber diameters than nanofibers produced from DMF. When the crystallinity of the 100 % PAN nanofibers were compared, the nanofibers electrospun from DMSO had the lowest crystallinity values. The tensile breaking stress values of the nanowebs produced from DMSO and NMP were higher than nanowebs produced from DMF while the breaking elongation values of the nanowebs produced from DMF was higher. Mechanical dispersion technique resulted in higher tensile breaking stress values than corresponding magnetic stirring. The redoping process also affected the tensile properties of the nanowebs by increasing the breaking stress values and decreasing the breaking elongation values. When DMSO was used as a solvent for the production of composite nanofibers, the electrical conductivity values at around 10(-6) S/cm were obtained corresponding to the semiconductive material range. The use of solvent mixtures resulted in better conductivity values than their counterparts. When CSA-NMP and CSA-NMP/DMF were compared, the nanofibers produced from the solvent mixture had higher conductivity values. On redoping, the conductivity increased 10 times and reached 1.2x10(-5) S/cm. The reference samples with DMSO had the lowest cyclization temperature and enthalpy. Addition of PANT increased the thermal stability of the composite nanofibers in comparison with pure PAN.&nbsp;This study was carried out to examine the effect of different solvents (DMSO, NMP, DMF) and solvent mixtures, application of dispersion and mixing techniques during solution preparation and redoping process on polyacrylonitrile (PAN) and camphorsulfonic acid (CSA) doped polyaniline (PANI) composite nanofibers. It was observed that nanofibers produced from DMSO and NMP solvents had larger fiber diameters than nanofibers produced from DMF. When the crystallinity of the 100 % PAN nanofibers were compared, the nanofibers electrospun from DMSO had the lowest crystallinity values. The tensile breaking stress values of the nanowebs produced from DMSO and NMP were higher than nanowebs produced from DMF while the breaking elongation values of the nanowebs produced from DMF was higher. Mechanical dispersion technique resulted in higher tensile breaking stress values than corresponding magnetic stirring. The redoping process also affected the tensile properties of the nanowebs by increasing the breaking stress values and decreasing the breaking elongation values. When DMSO was used as a solvent for the production of composite nanofibers, the electrical conductivity values at around 10-6 S/cm were obtained corresponding to the semiconductive material range. The use of solvent mixtures resulted in better conductivity values than their counterparts. When CSA-NMP and CSA-NMP/DMF were compared, the nanofibers produced from the solvent mixture had higher conductivity values. On redoping, the conductivity increased 10 times and reached 1.2&times;10-5 S/cm. The reference samples with DMSO had the lowest cyclization temperature and enthalpy. Addition of PANI increased the thermal stability of the composite nanofibers in comparison with pure PAN.</p