The Experts below are selected from a list of 11739 Experts worldwide ranked by ideXlab platform
Xia Wang - One of the best experts on this subject based on the ideXlab platform.
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coaxial electrospinning with triton x 100 solutions as sheath fluids for preparing pan Nanofibers
Macromolecular Materials and Engineering, 2012Co-Authors: Nicholas P. Chatterton, Xia Wang, Junhe Yang, Yaozu LiaoAbstract:Coaxial electrospinning using surfactants as sheath fluid for preparing high-quality Polymer Nanofibers is studied. PAN Nanofibers are fabricated using this process with Triton X-100 solutions in DMF. FESEM demonstrates that the Triton X-100 solution has a significant influence on the quality of the Nanofibers. The nanofiber diameters can be controlled by adjusting the concentration of Triton X-100 in the sheath fluids with a scaling law D = 640 C -0.32 . The mechanism of the influence of Triton X-100 solutions on the formation of PAN fibers is discussed and it is demonstrated that coaxial electrospinning with surfactant solution is a facile method for achieving high-quality Polymer Nanofibers.
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pvp Nanofibers prepared using co axial electrospinning with salt solution as sheath fluid
Materials Letters, 2012Co-Authors: Kenneth White, Xia Wang, Junhe Yang, Wei QianAbstract:Abstract A modified co-axial electrospinning process using salt solutions as sheath fluids for preparing Polymer Nanofibers was investigated. A series of polyvinylpyrrolidone (PVP) fibers were prepared with NaCl aqueous solutions at varying concentrations as sheath fluids. The sheath fluid had a significant influence on the formation of the compound Taylor cone. Scanning electron microscopy results demonstrated that the diameters of PVP Nanofibers could be manipulated through the concentration of NaCl solutions within an appropriate range. With 2 mg ml− 1 NaCl solution as sheath fluid, the smallest PVP Nanofibers, with a diameter of 120 ± 40 nm, were obtained. Co-axial electrospinning with salt solutions as sheath fluids is a facile method for achieving finer, homogeneous Polymer Nanofibers.
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polyacrylonitrile Nanofibers prepared using coaxial electrospinning with licl solution as sheath fluid
Nanotechnology, 2011Co-Authors: Christopher Branfordwhite, Xia Wang, Junhe YangAbstract:A modified coaxial electrospinning process including an electrolyte solution as sheath fluid was used for preparing high quality Polymer Nanofibers. A series of polyacrylonitrile (PAN) Nanofibers were fabricated utilizing a coaxial electrospinning containing LiCl in N, N-dimethylacetamide (DMAc) as the sheath fluid. FESEM results demonstrated that the sheath LiCl solutions have a significant influence on the quality of PAN Nanofibers. Nanofibers with smaller diameters, smoother surfaces and uniform structures were successfully prepared. The diameters of Nanofibers were controlled by adjusting the conductivity of the sheath fluid over a suitable range and this was determined by varying LiCl concentrations. The influence of the effect of LiCl on the formation of PAN fibers is discussed and it is concluded that coaxial electrospinning with electrolyte solutions is a convenient and facile process for achieving high quality Polymer Nanofibers.
Seeram Ramakrishna - One of the best experts on this subject based on the ideXlab platform.
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electrospun conducting Polymer Nanofibers and electrical stimulation of nerve stem cells
Journal of Bioscience and Bioengineering, 2011Co-Authors: Molamma P Prabhakaran, Laleh Ghasemimobarakeh, Guorui Jin, Seeram RamakrishnaAbstract:Tissue engineering of nerve grafts requires synergistic combination of scaffolds and techniques to promote and direct neurite outgrowth across the lesion for effective nerve regeneration. In this study, we fabricated a composite Polymeric scaffold which is conductive in nature by electrospinning and further performed electrical stimulation of nerve stem cells seeded on the electrospun Nanofibers. Poly-L-lactide (PLLA) was blended with polyaniline (PANi) at a ratio of 85:15 and electrospun to obtain PLLA/PANi Nanofibers with fiber diameters of 195 ± 30 nm. The morphology, chemical and mechanical properties of the electrospun PLLA and PLLA/PANi scaffolds were carried out by scanning electron microscopy (SEM), X-ray photo electron spectroscopy (XPS) and tensile instrument. The electrospun PLLA/PANi fibers showed a conductance of 3 × 10⁻⁹ S by two-point probe measurement. In vitro electrical stimulation of the nerve stem cells cultured on PLLA/PANi scaffolds applied with an electric field of 100 mV/mm for a period of 60 min resulted in extended neurite outgrowth compared to the cells grown on non-stimulated scaffolds. Our studies further strengthen the implication of electrical stimulation of nerve stem cells on conducting Polymeric scaffolds towards neurite elongation that could be effective for nerve tissue regeneration.
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microwave hall mobility and electrical properties of electrospun Polymer Nanofibers
Journal of Applied Physics, 2011Co-Authors: Jagadeesh V Babu, D V B Murthy, V Subramanian, V R K Murthy, T S Natarajan, Seeram RamakrishnaAbstract:Composite Nanofibers from poly(methylmethacrylate)- (PMMA-) conducting polyaniline [PANI(HCl)] were prepared by using the electrospinning technique. The morphology and structural details of the fibers were characterized by SEM and the ac conductivity of the composite fibers found was measured to be ∼ 2.17×10−4 S/cm which is very good enhancement compared to that of pure PMMA and conductivity of PANI-PMMA thin films as well. The conductivity is found to increase with increase in the polyaniline content in the composite. Microwave Hall mobility measurements on electrospun Nanofibers showed 17 cm2/V s for the lower loadings. With further increase in the polyaniline content in the composite, the mobility value decreases which is attributed to the increase in carrier-carrier scatterings.
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nanocomposite fabric formation by electrospinning and electrospraying technologies
Journal of Electrostatics, 2009Co-Authors: Anatol Jaworek, A T Sobczyk, Alexandre Krupa, Thomas Czech, Subramanian Sundarrajan, Seeram Ramakrishna, M. Lackowski, D. PliszkaAbstract:Abstract Electrospraying and electrospinning processes were employed for the production of nanocomposite material of Polymer Nanofibers blended with nanoparticles. The diameter of Polymer Nanofibers made of PVC, PSU or nylon was smaller than 500 nm. Metal oxide nanoparticles of TiO 2 , MgO, and Al 2 O 3 of the size 20–100 nm suspended in methanol were deposited on the Polymer Nanofibers. Three configurations of electrospray/electrospun nozzles used for the nanocomposite production were tested: 1. simultaneous electrospraying during the electrospinning process, 2. electrospraying onto the same rotating drum after the electrospinning is completed, and 3. electrospraying onto the electrospun mat removed from the drum and placed onto a heated table.
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recent development of Polymer Nanofibers for biomedical and biotechnological applications
Journal of Materials Science: Materials in Medicine, 2005Co-Authors: Yanzhong Zhang, Seeram Ramakrishna, Chwee Teck Lim, Zhengming HuangAbstract:Research in Polymer Nanofibers has undergone significant progress in the last one decade. One of the main driving forces for this progress is the increasing use of these Polymer Nanofibers for biomedical and biotechnological applications. This article presents a review on the latest research advancement made in the use of Polymer Nanofibers for applications such as tissue engineering, controlled drug release, wound dressings, medical implants, nanocomposites for dental restoration, molecular separation, biosensors, and preservation of bioactive agents.
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systematic parameter study for ultra fine fiber fabrication via electrospinning process
Polymer, 2005Co-Authors: S H Tan, Masaya Kotaki, Ryuji Inai, Seeram RamakrishnaAbstract:Processing parameters effects on the morphology such as fiber diameter and its uniformity of electrospun Polymer Nanofibers was investigated. A processing map summarized effects of solutions properties and processing conditions on the electrospun nanofiber morphology was obtained. Polymer concentration, its molecular weight, electrical conductivity of solvents were found as dominant parameters to control the morphology. Based on the systematic parameter study, electrospun PLLA fibers as small as 9 nm were successfully produced.
Dario Pisignano - One of the best experts on this subject based on the ideXlab platform.
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active Polymer Nanofibers for photonics electronics energy generation and micromechanics
Progress in Polymer Science, 2015Co-Authors: Luana Persano, Andrea Camposeo, Dario PisignanoAbstract:Abstract Active Polymer Nanofibers for opto- and nano-electronics benefit from low cost and versatile fabrication processes and exhibit an unequaled flexibility in terms of chemical composition, physical properties and achievable functionality. For these reasons, they have rapidly emerged as powerful tool for nanotechnologies and as building blocks of a wide range of devices. Both bottom up and top down nanofabrication concepts were developed to produce Nanofibers made of conjugated or other functional Polymers and blends. This article summarizes and reviews the chemico-physical and functional requirements for Polymer Nanofibers to be used in opto- and nanoelectronics, as well as recent advances in various promising device architectures, such as light emitting and photovoltaic devices, photodetectors, field-effect transistors, piezo- and thermoelectric generators, and actuators. The outlook of functional Polymer Nanofibers and of devices based on them is also outlined and discussed.
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distributed feedback imprinted electrospun fiber lasers
Advanced Materials, 2014Co-Authors: Luana Persano, Andrea Camposeo, Vito Fasano, Maria Moffa, Pompilio Del Carro, Rita Manco, Stefania Dagostino, Dario PisignanoAbstract:Imprinted, distributed feedback lasers are demonstrated on individual, active electrospun Polymer Nanofibers. In addition to advantages related to miniaturization, optical confinement and grating nanopatterning lead to a significant threshold reduction compared to conventional thin-film lasers. The possibility of imprinting arbitrary photonic crystal geometries on electrospun lasing Nanofibers opens new opportunities for realizing optical circuits and chips.
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Bright light emission and waveguiding in conjugated Polymer Nanofibers electrospun from organic-salt added solutions
Macromolecules, 2013Co-Authors: Vito Fasano, Andrea Camposeo, Alessandro Polini, Giovanni Morello, Maria Moffa, Dario PisignanoAbstract:Light emitting electrospun Nanofibers of poly-[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N'-diphenyl)-N,N'-di(p-butyl-oxy-phenyl)-1,4-diaminobenzene)] (PFO-PBAB) are produced by electrospinning under different experimental conditions. In particular, uniform fibers with average diameter of 180 nm are obtained by adding an organic salt to the electrospinning solution. The spectroscopic investigation assesses that the presence of the organic salt does not alter the optical properties of the active material, therefore providing an alternative approach for the fabrication of highly emissive conjugated Polymer Nanofibers. The produced Nanofibers display self-waveguiding of light, and polarized photoluminescence, which is especially promising for embedding active electrospun fibers in sensing and nanophotonic devices.
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Industrial upscaling of electrospinning and applications of Polymer Nanofibers: A review
Macromolecular Materials and Engineering, 2013Co-Authors: Luana Persano, Andrea Camposeo, Cagri Tekmen, Dario PisignanoAbstract:Electrospun Nanofibers are extensively studied and their potential applications are largely demonstrated. Today, electrospinning equipment and technological solutions, and electrospun materials are rapidly moving to commercialization. Dedicated companies supply laboratory and industrial-scale components and apparatus for electrospinning, and others commercialize electrospun products. This paper focuses on relevant technological approaches developed by research, which show perspectives for scaling-up and for fulfilling requirements of industrial production in terms of throughput, accuracy, and functionality of the realized Nanofibers. A critical analysis is provided about technological weakness and strength points in combination with expected challenges from the market.
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laser emission from electrospun Polymer Nanofibers
Small, 2009Co-Authors: Andrea Camposeo, Francesca Di Benedetto, Ripalta Stabile, Antonio Augusto Neves, Roberto Cingolani, Dario PisignanoAbstract:althoughelectrospinning (ES), based on the stretching of a Polymersolution under electrostatic forces, represents a practicallyunique technology that combines low cost and high through-put. Moreover, the addition of active components (i.e.,nanoparticles or molecular species) to the ES Polymersolution allows one to obtain composite nanofibers withspecific functionalities.
Xiangyang Shi - One of the best experts on this subject based on the ideXlab platform.
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organic inorganic nanohybrids formed using electrospun Polymer Nanofibers as nanoreactors
Coordination Chemistry Reviews, 2018Co-Authors: Zheng Qiao, Mingwu Shen, Yunchao Xiao, Meifang Zhu, Serge Mignani, Jean-pierre Majoral, Xiangyang ShiAbstract:Abstract This review article presents recent advances on the use of electrospun Nanofibers as nanoreactors to synthesize various organic/inorganic hybrid nanomaterials consisting of a Polymeric matrix hosting in situ generated inorganic nanoparticles (NPs) for different applications. Electrospun Nanofibers possess attractive properties such as controllable fiber diameters, high aspect ratio, and high surface area to volume ratio, affording their uses as a unique nanoreactor system to fabricate a range of organic/inorganic hybrid nanomaterials. In particular, the nanohybrids consisting of metal, metal oxide, metal sulfide, or metal chloride NPs can be in situ generated within the Polymeric fiber matrix via different reactions such as UV and microwave irradiation, chemical reduction, heating treatment, and galvanic replacement reaction. The formed organic/inorganic hybrid nanomaterials have been used for environmental remediation, catalysis, electronic and sensing devices, energy, wound dressing, etc. Some of the key developments in this area of research will be introduced in detail.
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fabrication of multiwalled carbon nanotube reinforced electrospun Polymer Nanofibers containing zero valent iron nanoparticles for environmental applications
Journal of Materials Chemistry, 2010Co-Authors: Shili Xiao, Mingwu Shen, Rui Guo, Shanyuan Wang, Qingguo Huang, Xiangyang ShiAbstract:A new approach to immobilizing zero-valent iron nanoparticles (ZVI NPs) into electrospun Polymer Nanofibers with enhanced mechanical properties for environmental applications is presented. In this approach, multiwalled carbon nanotubes (MWCNTs) are mixed with polyacrylic acid (PAA)/polyvinyl alcohol (PVA) mixture Polymer solution for subsequent electrospinning to form uniform Nanofibers. The MWCNT-incorporated PAA/PVA Nanofibers are crosslinked and then used as a nanoreactor to complex Fe(III) ions through binding with the PAA carboxyl groups for the reductive formation of ZVI NPs. The MWCNT-incorporated PAA/PVA Nanofibers before and after immobilization with ZVI NPs are characterized using scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and mechanical property measurements. We show that the mechanical properties of uniform nanofibrous mats with and without ZVI NPs are significantly enhanced even with only 1.0 wt% MWCNTs incorporated. The MWCNT-reinforced PAA/PVA nanofibrous mats containing ZVI NPs (1.6 nm) display excellent capability to decolorize model dyes such as methyl blue, acridine orange, and acid fuchsine with a decoloration percentage of more than 90%. Likewise, the same nanofibrous mats are found to be able to effectively degrade trichloroethylene, a model chlorinated hydrocarbon contaminant, with a degradation efficiency approaching 93%. The MWCNT-reinforced PAA/PVA nanofibrous mats may be used for generating other functionalized nanofiber-based complex materials with enhanced mechanical properties for applications in environmental remediation, catalysis, sensing, and biomedical sciences.
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polyelectrolyte multilayer assisted immobilization of zero valent iron nanoparticles onto Polymer Nanofibers for potential environmental applications
ACS Applied Materials & Interfaces, 2009Co-Authors: Shili Xiao, Mingwu Shen, Rui Guo, Shanyuan Wang, Qingguo Huang, Xiangyang ShiAbstract:We report a facile approach to synthesizing and immobilizing zero-valent iron nanoparticles (ZVI NPs) onto polyelectrolyte (PE) multilayer-assembled electrospun Polymer Nanofibers for potential environmental applications. In this approach, negatively charged cellulose acetate (CA) Nanofibers fabricated by electrospinning were assembled with multilayers of poly(diallyldimethylammonium chloride) (PDADMAC) and polyacrylic acid (PAA) through electrostatic layer-by-layer assembly. The formed PAA/PDADMAC multilayers onto CA Nanofibers were then used as a nanoreactor to complex Fe(II) ions through the binding with the free carboxyl groups of PAA for subsequent reductive formation of ZVI NPs. Combined scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetry analysis studies demonstrate that the ZVI NPs are successfully synthesized and uniformly distributed into the PE multilayers assembled onto the CA Nanofibers. ...
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immobilization of zerovalent iron nanoparticles into electrospun Polymer Nanofibers synthesis characterization and potential environmental applications
Journal of Physical Chemistry C, 2009Co-Authors: Shili Xiao, Mingwu Shen, Rui Guo, Shanyuan Wang, Xiangyang ShiAbstract:We present a facile approach to immobilizing zerovalent iron nanoparticles (ZVI NPs) into electrospun Polymer nanofibrous mats. Electrospun poly(acrylic acid) (PAA)/poly(vinyl alcohol) (PVA) nanofibrous mats were treated at an elevated temperature to render them water stable. The water-insoluble nanofibrous mats were then used as nanoreactors to complex ferric iron for subsequent formation and immobilization of ZVI NPs. Scanning electron microscopy (SEM) studies show that the smooth, uniform morphology of the electrospun nanofibrous mats does not significantly change after immobilization with ZVI NPs. Energy-dispersive spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED), and thermogravimetric analysis (TGA) were used to characterize the Polymer Nanofibers before and after the immobilization of ZVI NPs. We show that the formed ZVI NPs are uniformly distributed into the electrospun Nanofibers with a mean partic...
Tengfei Luo - One of the best experts on this subject based on the ideXlab platform.
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crystalline Polymer Nanofibers with ultra high strength and thermal conductivity
Nature Communications, 2018Co-Authors: Ramesh Shrestha, Bikramjit Chatterjee, Teng Zheng, Zeyu Liu, Tengfei Luo, Sukwon Choi, Kedar Hippalgaonkar, Maarten P De Boer, Sheng ShenAbstract:Polymers are widely used in daily life, but exhibit low strength and low thermal conductivity as compared to most structural materials. In this work, we develop crystalline Polymer Nanofibers that exhibit a superb combination of ultra-high strength (11 GPa) and thermal conductivity, exceeding any existing soft materials. Specifically, we demonstrate unique low-dimensionality phonon physics for thermal transport in the Nanofibers by measuring their thermal conductivity in a broad temperature range from 20 to 320 K, where the thermal conductivity increases with increasing temperature following an unusual ~T1 trend below 100 K and eventually peaks around 130-150 K reaching a metal-like value of 90 W m-1 K-1, and then decays as 1/T. The Polymer Nanofibers are purely electrically insulating and bio-compatible. Combined with their remarkable lightweight-thermal-mechanical concurrent functionality, unique applications in electronics and biology emerge.
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Polymer Nanofibers with outstanding thermal conductivity and thermal stability fundamental linkage between molecular characteristics and macroscopic thermal properties
Journal of Physical Chemistry C, 2014Co-Authors: Teng Zhang, Tengfei LuoAbstract:Polymer Nanofibers with high thermal conductivities and outstanding thermal stabilities are highly desirable in heat transfer-critical applications such as thermal management, heat exchangers, and energy storage. In this work, we unlock the fundamental relations between the thermal conductivity and thermal stability of Polymer Nanofibers and their molecular characteristics by studying the temperature-induced phase transitions and thermal transport of a series of Polymer Nanofibers. Ten different Polymer Nanofibers with systematically chosen molecular structures are studied using large-scale molecular dynamics simulations. We found that high thermal conductivity and good thermal stability can be achieved in Polymers with rigid backbones, exemplified by π-conjugated Polymers, due to suppressed segmental rotations and large phonon group velocities. The low probability of segmental rotation not only prevents temperature-induced phase transition but also enables long phonon mean free paths due to reduced disor...
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Polymer Nanofibers with outstanding thermal conductivity and thermal stability fundamental linkage between molecular characteristics and macroscopic thermal properties
arXiv: Chemical Physics, 2014Co-Authors: Teng Zhang, Tengfei LuoAbstract:Polymer Nanofibers with high thermal conductivities and outstanding thermal stabilities are highly desirable in heat transfer-critical applications such as thermal management, heat exchangers and energy storage. In this work, we unlock the fundamental relations between the thermal conductivity and thermal stability of Polymer Nanofibers and their molecular characteristics by studying the temperature-induced phase transitions and thermal transport of a series of Polymer Nanofibers. Ten different Polymer Nanofibers with systematically chosen molecular structures are studied using large scale molecular dynamics simulations. We found that high thermal conductivity and good thermal stability can be achieved in Polymers with rigid backbones, exemplified by {\pi}-conjugated Polymers, due to suppressed segmental rotations and large phonon group velocities. The low probability of segmental rotation does not only prevent temperature-induced phase transition but also enables long phonon mean free paths due to reduced disorder scattering. Although stronger inter-chain interactions can also improve the thermal stability, Polymers with such a feature usually have heavier atoms, weaker backbone bonds, and segments vulnerable to random rotations, which lead to low thermal conductivities. This work elucidates the underlying linkage between the molecular nature and macroscopic thermal properties of Polymer Nanofibers, which is instrumental to the design of thermally conductive Polymer Nanofibers with high temperature stabilities.