Graphene based all-solid-state supercapacitors with ionic liquid incorporated polyacrylonitrile electrolyte

This paper presents an idea of using carbonized electrospun Polyacrylonitrile (PAN) fibers as a sensor material in a structural health monitoring (SHM) system. The electrospun PAN fibers are lightweight, less costly and do not interfere with the functioning of infrastructure. This study deals with the fabrication of PAN-based nanofibers via electrospinning followed by stabilization and carbonization in order to remove all non-carbonaceous material and ensure pure carbon fibers as the resulting material. Electrochemical impedance spectroscopy was used to determine the ionic conductivity of PAN fibers. The X-ray diffraction study showed that the repeated peaks near 42° on the activated nanofiber film were α and β phases, respectively, with crystalline forms. Contact angle, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were also employed to examine the surface, thermal and chemical properties of the carbonized electrospun PAN fibers. The test results indicated that the carbonized PAN nanofibers have superior physical properties, which may be useful for structural health monitoring (SHM) applications in different industries.

Thermal, Electrical and Surface Hydrophobic Properties of Electrospun Polyacrylonitrile Nanofibers for Structural Health Monitoring.

To address the worldwide issue of water scarcity, which is threatening our sustainable economic development and ecological security, an efficient water-collecting surface with fast-capturing capability and easy drainage is essential. Inspired by the fog-harvesting capability of Stenocara beetles in the Namib Desert, this study presents an easy method for fabricating flexible, permanent, electrospun superhydrophobic–hydrophilic polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA) nanocomposite fiber mats for atmospheric fog water harvesting. This combination of a hydrophobic PAN domain and hydrophilic nanomaterials causes water to condense on the hydrophilic micro and nanoparticles and roll off the hydrophobic nanofibers. By adjusting the proportion of micro and nanomaterials, we can tune the fog water harvesting efficiency. The superhydrophobic–hydrophilic nanocomposite fibers are fabricated with various proportions of titanium dioxide (TiO2) nanoparticles and aluminum (Al) microparticles using the electrospinning technique followed by stabilization and carbonization to remove all non-carbonaceous materials from the fiber structures. The fiber morphology, surface hydrophobicity, crystal structure, and fog-harvesting performance of the nanocomposite fibers were investigated. A water contact angle of 154.8° was achieved with the addition of a 10% inclusion of combined micro- and nanoparticles. The experimental tests of these nanocomposites demonstrated the feasibility of the freshwater production with a daily water productivity of more than 1.49 liter m−2 of the nanocomposites. It is estimated that the material cost of making such nanocomposites to supply minimum daily water consumption for a household with 2 members (i.e., 6 liters) is only $4.96 (USD). These nanocomposites are cheap and affordable, and require no additional input of energy, and are especially suitable for clean water production in arid areas. This work offers a very feasible and novel tool to achieve the mass production of water-harvesting materials.

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A highly efficient fog harvester of electrospun permanent superhydrophobic–hydrophilic polymer nanocomposite fiber mats

The chemical resemblance of HA to natural bone has led to a widespread research approach to use synthetic HA as a bone substitute and replacement in biomedical application. Nanofibrous composites comprised of bioactive HA has been considered as a promising material for bone regeneration. However, the inadequate mechanical performance by HA agglomeration on nanofiber polymer matrix during electrospinning is a demanding challenge. In this study, we fabricated composite nanofibrous scaffold from the blends of PAN, nCB, and HA via electrospinning to observe the effect of nCB on the membrane properties. All the prepared samples were characterized by SEM-EDX, TEM, FTIR, XRD, TGA, water contact angle, swelling, and tensile strength test. Mineralized samples were also characterized by SEM-EDX, FTIR, XRD, and XPS. Incorporation of nCB reduced the average diameter of nanofibers without any significant changes in surface morphology in PAN/nCB scaffold. EDX spectra demonstrated an incremental increase in HA components with an increase in the amount of HA loading. TEM micrographs revealed dispersed nCB on the nanofibrous structure. Significant improvement in mechanical performance was observed in PAN/nCB/HA compared to PAN/HA scaffolds. Although an increase in the amount of HA in PAN/nCB/HA caused a reduction in the tensile strength and Young's modulus, the values were still greater than those without nCB. PAN/nCB/HA composite scaffold showed excellent mineralization of HA (Ca/P = 1.68) with platelet-like clustered protrusions (typical HA morphology) after incubation in SBF. MC3T3-E1 osteoblast cells showed excellent proliferation and adhesion on our prepared membranes. Our findings have demonstrated that nCB can strengthen the HA-based polymeric nanofibers and such biocompatible composites have strong potential to be used as bone and other hard tissue restoring materials.

Polyacrylonitrile/Carbon Black nanoparticle/Nano-Hydroxyapatite (PAN/nCB/HA) composite nanofibrous matrix as a potential biomaterial scaffold for bone regenerative applications

N. F. Konnova

Papers

Thermographic and thermogravimetric analysis of the thermal behaviour of polyacrylonitrile fibres