1D Nanofibers Research Articles

Comparative Microstructural Study on Mechanical Properties of Concrete Enhanced with Graphite and Graphene Compound

The present study is based on nano technology and came up with the idea of introducing nanoparticles in the raw materials used for construction. Nano materials are available in three principal shapes 0, 1 and 2 Dimensional nanoparticles. 0D and 1D nanofibers are such as carbon nanotubes and nanosilica compounds. This study has investigated the physical and chemical properties of graphite and graphene compound and its applicability in construction industry. Graphene has created interest as it is believed to improve the strength of concrete allowing the possibility of controlling properties of concrete. In this work graphene is used as a reinforcing additive in cement-based mortar and concrete. Own Graphene compound is prepared using conventional graphite and concentrated hydrogen peroxide in the laboratory due to the unavailability of graphene. As a part of microstructural investigation, SEM and EDS analysis on graphite and graphene compounds before and after implementation are carried out in the laboratory. Then the two compounds are replaced as a part of small percentage in cement mortar cubes casted for various proportions. The mechanical properties of cement-based composites are studied after incorporating of graphite and graphene compounds at low dosages in concrete and then the results are compared.

A Natural Triterpene Saponin-Based Pickering Emulsion.

The abuse of chemical surfactants in pesticide formulations is a potential threat to agricultural development and environmental safety. Thereby, developing an efficient eco-friendly pesticide formulation is of great significance. In this research, a biocompatible and ultrastable pesticide formulation has been developed in which merely 1 wt % natural glycyrrhizic acid (GA) was used to emulsify and stabilize 80 wt % agricultural oils. During the preparation process, amphiphilic GA molecules initially self-assembled into 1D nanofibers with a favorable surfactivity, and then afforded GA-based Pickering emulsions with fine droplets. Consequently, the Pickering emulsions transformed into gel-like Pickering emulsions as a result of the formation of a 3D network of nanofibers. On account of the unique chemical structure and admirable assembly behavior of GA, the gel-like Pickering emulsions exhibit ultrastability, thixotropy, and broad pH resistance. In addition, this formulation was investigated for its potential application to pesticides by using pure carbosulfan as the oil phase; up to 60 wt % carbosulfan could be coated, which is more than in the current commercial formulations. This work not only provides new insights into the application of natural biosurfactants to pesticides, but also proposes a biocompatible and eco-friendly pesticide formulation for use in ecological agriculture.

Atomic Layer Deposition of Ruthenium Nanoparticles on Electrospun Carbon Nanofibers: A Highly Efficient Nanocatalyst for the Hydrolytic Dehydrogenation of Methylamine Borane.

We report the fabrication of a novel and highly active nanocatalyst system comprising electrospun carbon nanofiber (CNF)-supported ruthenium nanoparticles (NPs) (Ru@CNF), which can reproducibly be prepared by the ozone-assisted atomic layer deposition (ALD) of Ru NPs on electrospun CNFs. Polyacrylonitrile (PAN) was electropsun into bead-free one-dimensional (1D) nanofibers by electrospinning. The electrospun PAN nanofibers were converted into well-defined 1D CNFs by a two-step carbonization process. We took advantage of an ozone-assisted ALD technique to uniformly decorate the CNF support by highly monodisperse Ru NPs of 3.4 ± 0.4 nm size. The Ru@CNF nanocatalyst system catalyzes the hydrolytic dehydrogenation of methylamine borane (CH3NH2BH3), which has been considered as one of the attractive materials for the efficient chemical hydrogen storage, with a record turnover frequency of 563 mol H2/mol Ru × min and an excellent conversion (>99%) under air at room temperature with the activation energy ( Ea) of 30.1 kJ/mol. Moreover, Ru@CNF demonstrated remarkable reusability performance and conserved 72% of its inherent catalytic activity even at the fifth recycle.

Synthesis and characterization of Sr1-xLaxMnO3/SiOC nanocomposites decorated with 1D nanostructures for high temperature CO2 splitting

1D nanostructures of Lanthanum Strontium Manganite (LSM) are tested as thermochemical catalyst for CO2 splitting. The manganite precursors were incorporated into a ceramic silicon oxycarbide (SiOC) matrix at two different stages during its synthesis to form the nanocomposites. As a result, the LSM nanostructures decorate the large-size pores of the SiOC matrix in form of 1D nanofibers and nanowires. At the same time, the formation of the SiOC units decreases because of the incorporation of these LSM. Moreover, the synthetic strategy strongly affects the surface parameter related to apolar interactions. It turns out that the surface fractal constant of the nanocomposite determines the reactivity of the LSM materials towards CO2. This reactivity has been verified by collecting the spectra of the gases involved in the thermochemical reactions and determining the relative CO2 concentration as a function of the temperature.

Highly-damped nanofiber mesh for ultrasensitive broadband acoustic flow detection

Many small animals have evolved ultrasensitive hearing capability by detecting acoustic flow with mechanosensory hair-like structures. The highly-damped hairy structures such as the fluffy mosquito antennae are driven to move by viscous forces in the fluctuating medium, in contrast to sensing acoustic pressure with tympanal membranes. Inspired by the acoustic flow sensing of animals, the highly-damped 2D nanofiber mesh is presented here for the ultrasensitive, broadband acoustic flow detection. By evaporating 90 nm Au on a freestanding electrospun Poly(methyl methacrylate) (PMMA) nanofiber mesh, we fabricate a thin layer of conductive Au-PMMA nanomesh with dimensions 8 mm × 8 mm, with thickness of approximately 3 μm and average fiber diameter around 430 nm. The nanomesh is shown to move instantaneously with broadband fluctuating airflow near maximum physical efficiency from 100 Hz to 10 000 Hz, i.e. , surpassing the frequency response and efficiency of previously-reported microscale hairy structures. By transducing the motion of the nanomesh with electromagnetic induction, we demonstrate fluctuating airflow detection with almost full fidelity in the measured frequency range. Sensing flow with highly-damped nanomaterials will benefit miniaturized flow measurement and sound detection, and provides an important application for the diverse flourishing nanomaterials, such as 1D nanofibers, 2D nanomeshes, and 3D nanolattices.

Transformation from Nanofibers to Nanoribbons in Poly(3-hexylthiophene) Solution by Adding Alkylthiols.

An intriguing morphological transition from poly(3-hexylthiophene) (P3HT) 1D nanofibers to 2D nanoribbons enabled by the addition of a series of alkylthiols is reported. First, P3HT 1D nanofibers are formed due to strong anisotropic π-π stacking between planar rigid backbones. Upon the addition of alkylthiols, P3HT nanofibers are transformed into nanoribbons associated with the crystallographic transition from edge-on orientation to flat-on orientation. The content of alkylthiols has a great influence on the P3HT morphology in the solution. The mechanism of such a morphological transformation is discussed based on the interaction between alkylthiols and P3HT chains. This work offers an effective strategy to tailor the crystal morphology and dimension of P3HT, which not only improves the understanding of P3HT crystallization but also may enable such discovery into conjugated polymer-based optoelectronic devices.

Electrospinning: An enabling nanotechnology platform for drug delivery and regenerative medicine.

Electrospinning provides an enabling nanotechnology platform for generating a rich variety of novel structured materials in many biomedical applications including drug delivery, biosensing, tissue engineering, and regenerative medicine. In this review article, we begin with a thorough discussion on the method of producing 1D, 2D, and 3D electrospun nanofiber materials. In particular, we emphasize on how the 3D printing technology can contribute to the improvement of traditional electrospinning technology for the fabrication of 3D electrospun nanofiber materials as drug delivery devices/implants, scaffolds or living tissue constructs. We then highlight several notable examples of electrospun nanofiber materials in specific biomedical applications including cancer therapy, guiding cellular responses, engineering in vitro 3D tissue models, and tissue regeneration. Finally, we finish with conclusions and future perspectives of electrospun nanofiber materials for drug delivery and regenerative medicine.

Large scale synthesis of 3D nanoflowers of SnO2/TiO2 composite via electrospinning with synergistic properties

Composite of two metal oxides, SnO2 and TiO2, is synthesized as 3D nanoflowers in large quantities by electrospinning technique. They show superior energy storage properties and photocatalytic performance than their components or conventional electrospun 1D nanofibers.

Construction of 3D Carbon Nanostructure: Carbon Nanosheets Decorated Carbon Nanofiber As a Three-Dimensional Carbon Hybrid for High Performance Lithium-Sulfur Battery

Among the emerging energy storage methods, lithium-sulfur battery (LiS) has drawn plenty of attentions due to its high theoretical energy density (2600 Wh kg-1),1 economical cost and environmental benignity. Nevertheless, the insulating nature of sulfur and notorious polysulfides shuttling result in a low sulfur utilization and short cycling life.2 To address these problems, carbon material has been confirmed as an ideal sulfur host to promote LiS’s performance because of their low cost, high conductivity and controllable structure such as carbon spheres, carbon nanotube/fibers and carbon nanosheets. For example, one-dimensional carbon nanotube can increase the sulfur utilization by providing better electrical conductivity. However, its “open-to-electrolyte” structures cannot effectively prevent shuttling effect.3 As for zero-dimension carbon materials, core/yolk shell carbon spheres in particular, are less capable of establishing conductive networks, which in turns, compromise the sulfur utilization and rate capability.4 Thus, it is of great necessity to develop three-dimensional (3D) carbon materials with multiple functions in order to achieve high-performance lithium-sulfur batteries. Along this line, we prepared a three-dimensional carbon nanosheets modified carbon nanofiber (3DCNF) as high porosity sulfur host. After decorated with vertically aligned carbon nanosheets, the surface area of pristine carbon nanofiber was dramatically increased from 30 m2/g to 500 m2/g due to the expanded dimension. Although both 1D nanofiber and 2D nanosheets cannot effectively prevent polysulfides shuttling by themselves, the delicate combination of them endows new functions, where 3D carbon hybrid is capable of accommodating sulfur expansion and deterring polysulfides dissolution by the hierarchical porous structure and interconnected carbon nanosheets. At the same time, the 3D porous carbon nanofiber can also form conductive network that allows rapid electron transfer. With the structural advantages, the 3DCNF and sulfur composite delivered a capacity as high as 1266, 977 mAh/g at 0.1 and 0.5 C, respectively. After 500 cycles at 0.5 C, it still retains a capacity of 607 mAh/g (0.07% capacity fading per cycle), exhibiting excellent cycling capability. Reference M. K. Song, E. J. Cairns and Y. Zhang, Nanoscale, 2013, 5, 2186-2204.Y. Yang, G. Zheng and Y. Cui, Chem. Soc. Rev., 2013, 42, 3018-3032.X. Liang, Z. Wen, Y. Liu, H. Zhang, J. Jin, M. Wu and X. Wu, J. Power Sources, 2012, 206, 409-413.Y. J. Hong, J.-K. Lee and Y. Chan Kang, J. Mater. Chem. A, 2017, 5, 988-995. Figure 1

Photocontrolled Coumarin-diphenylalanine/Cyclodextrin Cross-Linking of 1D Nanofibers to 2D Thin Films.

Using coumarin-modified diphenylalanine (CO-FF) and γ-cyclodextrin (γ-CD) as building blocks, we successfully constructed one-dimensional nanofibers with several nanometers in width and tens of micrometers in length. Through the photodimerization of coumarin units in CO-FF⊂γ-CD complexes, the resultant nanofibers could be cross-linked to organic 2D thin films with a lateral dimension of tens of micrometers and a thickness of nanometers. The resultant thin films exhibited a significant fluorescence enhancement for twisted intramolecular charge-transfer (TICT) molecules and effective removal of pollutant from water through filtration. This 1D → 2D morphological conversion controlled by light may provide a novel strategy to construct the highly ordered nanostructures that can be used as templates for making nanoscaled materials with defined sizes and shapes.

Metal Oxide-Assisted PEDOT Nanostructures via Hydrolysis-Assisted Vapor-Phase Polymerization for Energy Storage

The diversity of nanostructures obtained from organic polymerization is limited when compared to the huge amount of documented inorganic nanostructures. In this paper, we elucidate a synergistic mechanism between in situ inorganic salt hydrolysis and vapor-phase polymerization for the metal oxide-poly(3,4-ethylenedioxythiophene) (PEDOT) hybrid nanostructure growth. The steady state polymer growth and kinetically controlled hydrolysis enables homogeneous deposition of high-aspect-ratio crystal phases such as β-FeOOH, TeO2, and SnO2 coated by a conducting polymer. By controlling the hydrolysis kinetics, the hybrid material is synthesized in one step with morphologies controlled from 1D nanofibers to 2D nanoflowers and nanostructures from monolithic to core–shell. This fundamental understanding of the connection between hydrolysis and polymerization allows the future development of nanostructured inorganic, polymeric, and inorganic–organic hybrid materials. Enabled by this study, electrodes for energy storag...

Synthesis of SiC nanofibers from a natural biopolymer via carbothermal reduction method

One-dimensional (1D) nanofibers have recently attracted a great interest for a wide range of advanced applications due to their unique structural characteristics such as high length/diameter ratio and high surface area. In the present work, a convenient method has been applied to prepare 1D silicon carbide (SiC) nanofibers by using a natural biopolymer, silk cocoon, as an economical precursor. By applying a post heat treatment including the combination of pre-oxidization, cyclization, and single step carbothermal reduction treatment, the coated silk cocoon fibers (fibroins) by tetraethyl orthosilicate (TEOS) sol, can be transformed into 1D SiC nanofibers of 193-295 nm diameter composed of SiC nanoparticles of 20 nm.

Cell Migration in 1D and 2D Nanofiber Microenvironments

Understanding how cells migrate in fibrous environments is important in wound healing, immune function, and cancer progression. A key question is how fiber orientation and network geometry influence cell movement. Here we describe a quantitative, modeling-based approach toward identifying the mechanisms by which cells migrate in fibrous geometries having well controlled orientation. Specifically, U251 glioblastoma cells were seeded onto non-electrospinning Spinneret based tunable engineering parameters fiber substrates that consist of networks of suspended 400 nm diameter nanofibers. Cells were classified based on the local fiber geometry and cell migration dynamics observed by light microscopy. Cells were found in three distinct geometries: adhering two a single fiber, adhering to two parallel fibers, and adhering to a network of orthogonal fibers. Cells adhering to a single fiber or two parallel fibers can only move in one dimension along the fiber axis, whereas cells on a network of orthogonal fibers can move in two dimensions. We found that cells move faster and more persistently in 1D geometries than in 2D, with cell migration being faster on parallel fibers than on single fibers. To explain these behaviors mechanistically, we simulated cell migration in the three different geometries using a motor-clutch based model for cell traction forces. Using nearly identical parameter sets for each of the three cases, we found that the simulated cells naturally replicated the reduced migration in 2D relative to 1D geometries. In addition, the modestly faster 1D migration on parallel fibers relative to single fibers was captured using a correspondingly modest increase in the number of clutches to reflect increased surface area of adhesion on parallel fibers. Overall, the integrated modeling and experimental analysis shows that cell migration in response to varying fibrous geometries can be explained by a simple mechanical readout of geometry via a motor-clutch mechanism.

Urchin-like V2O3/C Hollow Nanosphere Hybrid for High-Capacity and Long-Cycle-Life Lithium Storage

Vanadium oxides (VOx) show potential in Li-ion batteries (LIBs) originating from their abundance, low cost, and high theoretical capacities. Although V2O3 exhibits a high theoretical capacity of 1070 mAh g–1, most of the current reported for V2O3-based anodes suffer from poor electrical conductivity and huge volume change upon cycling in practice. Herein, an urchin-like V2O3/C hybrid composed of 1D nanofibers (a length-to-diameter ratio of 4) and hollow nanospheres (a diameter of 200–300 nm) has been synthesized via a template-free solvothermal method combined with a carbothermal reduction strategy. Both the nanofibers and hollow nanospheres consist of carbon-coated V2O3 nanostructures. During the solvothermal process, glucose plays not only as the carbon resource but also as the structural direction agent of nanosphere structures, and the formation of 1D V2O3 nanofibers is attributed to the epitaxial growth of V2O3 nanoparticles on the outer surface of nanosheets. When applied as an LIB anode, the hybrid...

Fabrication of MgTiO3 nanofibers by electrospinning and their photocatalytic water splitting activity

The photocatalytic H2 evolution from water splitting is a promising process for generating renewable energy. In regard of the fascinating properties of the one-dimensional (1D) nanostructure, when used as photocatalyst, we report the synthesis of MgTiO3 1D nanofibers by the electrospinning technique and the investigations of their photocatalytic performance. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) corporately confirmed the successful fabrication of pure MgTiO3 nanofibers. By contrast, the MgTiO3 nanoparticles obtained via sol-gel method still contains impurities because of the inhomogeneous crystallization. The MgTiO3 nanofibers exhibited enhanced efficiency and stability in photocatalytic H2 generation under ultraviolet light, compared with the MgTiO3 nanoparticles and P25. The photoelectrochemical measurements further revealed that MgTiO3 nanofibers facilitated the transport and separation of the photoinduced charge carriers, mainly resulting from their special 1D structure, unique mesh morphology, large specific surface area and pure phase.

Dimensional Control and Morphological Transformations of Supramolecular Polymeric Nanofibers Based on Cofacially-Stacked Planar Amphiphilic Platinum(II) Complexes.

Square-planar platinum(II) complexes often stack cofacially to yield supramolecular fiber-like structures with interesting photophysical properties. However, control over fiber dimensions and the resulting colloidal stability is limited. We report the self-assembly of amphiphilic Pt(II) complexes with solubilizing ancillary ligands based on polyethylene glycol [PEGn, where n = 16, 12, 7]. The complex with the longest solubilizing PEG ligand, Pt-PEG16, self-assembled to form polydisperse one-dimensional (1D) nanofibers (diameters <5 nm). Sonication led to short seeds which, on addition of further molecularly dissolved Pt-PEG16 complex, underwent elongation in a "living supramolecular polymerization" process to yield relatively uniform fibers of length up to ca. 400 nm. The fiber lengths were dependent on the Pt-PEG16 complex to seed mass ratio in a manner analogous to a living covalent polymerization of molecular monomers. Moreover, the fiber lengths were unchanged in solution after 1 week and were therefore "static" with respect to interfiber exchange processes on this time scale. In contrast, similarly formed near-uniform fibers of Pt-PEG12 exhibited dynamic behavior that led to broadening of the length distribution within 48 h. After aging for 4 weeks in solution, Pt-PEG12 fibers partially evolved into 2D platelets. Furthermore, self-assembly of Pt-PEG7 yielded only transient fibers which rapidly evolved into 2D platelets. On addition of further fiber-forming Pt complex (Pt-PEG16), the platelets formed assemblies via the growth of fibers selectively from their short edges. Our studies demonstrate that when interfiber dynamic exchange is suppressed, dimensional control and hierarchical structure formation are possible for supramolecular polymers through the use of kinetically controlled seeded growth methods.

Polysulfide-Breathing/Dual-Conductive, Heterolayered Battery Separator Membranes Based on 0D/1D Mingled Nanomaterial Composite Mats.

Facile/sustainable utilization of sulfur active materials is an ultimate challenge in high-performance lithium-sulfur (Li-S) batteries. Here, as a membrane-driven approach to address this issue, we demonstrate a new class of polysulfide-breathing (capable of reversibly adsorbing and desorbing polysulfides)/dual (electron and ion) conductive, heterolayered battery separator membranes (denoted as "MEC-AA separators") based on 0D (nanoparticles)/1D (nanofibers) composite mats. The MEC-AA separator is fabricated through an in-series, concurrent electrospraying/electrospinning process. The top layer of the MEC-AA separator comprises close-packed mesoporous MCM-41 nanoparticles spatially besieged by multiwalled carbon nanotubes (MWNT) wrapped poly(ether imide) (PEI) nanofibers. The MCM-41 in the top layer shows reversible adsorption/desorption of polysulfides, and the MWNT-wrapped PEI nanofibers act as a dual-conductive upper current collector. Preferential deposition of the MWNTs along the PEI nanofibers and dispersion state of the separator components are elucidated theoretically using computational methods. The support layer, which consists of densely packed Al2O3 nanoparticles and polyacrylonitrile nanofibers, serves as a mechanically/thermally stable and polysulfide-capturing porous membrane. The unique structure and multifunctionality of the MEC-AA separator allow for substantial improvements in redox reaction kinetics and cycling performance of Li-S cells far beyond those achievable with conventional polyolefin separators. The heterolayered nanomat-based membrane strategy opens a new route toward electrochemically active/permselective advanced battery separators.

Effect of Ag Loading on the Microstructure of TiO2 Electrospun Nanofibers

In this research work, crystalline structure, phase transformation, morphology and mean size of titanium dioxide (TiO2) electrospun nanofibers have been tailored by loading with 2.5, 5.0 and 7.5 wt.% of silver (Ag) which was followed by calcination. The as prepared non woven mats of nanofibers were calcinated at 500 °C to allow the reaction moieties to leave the TiO2 matrix and subsequently formation of Ag clusters. The effect of Ag loading and calcination on the transformation of microstructure of these electrospun nanofibers have been characterized by XRD, FESEM, FT-IR and Raman spectroscopy (RS). The mean diameter of Ag loaded nanofibers has been found to decrease upon calcination which was estimated to 70 nm whereas length was in the order of mm range. XRD and RS results have strongly supported the transformation of crystalline phase from rutile (A) to anatase (R) above 2.5 wt.% of Ag loading in TiO2 after calcination. The roughness on the outer surfaces of these nanofibers has been observed to increase with the Ag loading consequent to calcination, which has been attributed to the formation Ag nanoparticles that were found adsorbed at the surfaces. An interesting finding of this study is the existence of 1D nanofibers’ structure even at higher (7.5 wt.%) Ag loading, as observed by the SEM micrographs.

Nanoengineering Hybrid Supramolecular Multilayered Biomaterials Using Polysaccharides and Self‐Assembling Peptide Amphiphiles

Developing complex supramolecular biomaterials through highly dynamic and reversible noncovalent interactions has attracted great attention from the scientific community aiming key biomedical and biotechnological applications, including tissue engineering, regenerative medicine, or drug delivery. In this study, the authors report the fabrication of hybrid supramolecular multilayered biomaterials, comprising high‐molecular‐weight biopolymers and oppositely charged low‐molecular‐weight peptide amphiphiles (PAs), through combination of self‐assembly and electrostatically driven layer‐by‐layer (LbL) assembly approach. Alginate, an anionic polysaccharide, is used to trigger the self‐assembling capability of positively charged PA and formation of 1D nanofiber networks. The LbL technology is further used to fabricate supramolecular multilayered biomaterials by repeating the alternate deposition of both molecules. The fabrication process is monitored by quartz crystal microbalance, revealing that both materials can be successfully combined to conceive stable supramolecular systems. The morphological properties of the systems are studied by advanced microscopy techniques, revealing the nanostructured dimensions and 1D nanofibrous network of the assembly formed by the two molecules. Enhanced C2C12 cell adhesion, proliferation, and differentiation are observed on nanostructures having PA as outermost layer. Such supramolecular biomaterials demonstrate to be innovative matrices for cell culture and hold great potential to be used in the near future as promising biomimetic supramolecular nanoplatforms for practical applications.

Multifunctional CaSc2O4:Yb3+/Er3+ one-dimensional nanofibers: electrospinning synthesis and concentration-modulated upconversion luminescent properties

In this paper, an electrospinning technique was developed to prepare CaSc2O4:Yb3+/Er3+ one dimensional (1D) nanofibers for the first time.