scholarly journals Mechanical and Dielectric Properties of Aligned Electrospun Fibers

Fibers ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 4
Author(s):  
Blesson Isaac ◽  
Robert M. Taylor ◽  
Kenneth Reifsnider
Keyword(s):  
Dielectric Properties ◽  
Dielectric Property ◽  
Electrospun Nanofibers ◽  
Cold Drawing ◽  
General Interest ◽  
Electrospun Fibers ◽  
Energy Storage Devices ◽  
Electrospinning Technique ◽  
Specific Strength ◽  
Aligned Nanofibers

This review paper examines the current state-of-the-art in fabrication of aligned fibers via electrospinning techniques and the effects of these techniques on the mechanical and dielectric properties of electrospun fibers. Molecular orientation, system configuration to align fibers, and post-drawing treatment, like hot/cold drawing process, contribute to better specific strength and specific stiffness properties of nanofibers. The authors suggest that these improved, aligned nanofibers, when applied in composites, have better mechanical and dielectric properties for many structural and multifunctional applications, including advanced aerospace applications and energy storage devices. For these applications, most fiber alignment electrospinning research has focused on either mechanical property improvement or dielectric property improvement alone, but not both simultaneously. Relative to many other nanofiber formation techniques, the electrospinning technique exhibits superior nanofiber formation when considering cost and manufacturing complexity for many situations. Even though the dielectric property of pure nanofiber mat may not be of general interest, the analysis of the combined effect of mechanical and dielectric properties is relevant to the present analysis of improved and aligned nanofibers. A plethora of nanofibers, in particular, polyacrylonitrile (PAN) electrospun nanofibers, are discussed for their mechanical and dielectric properties. In addition, other types of electrospun nanofibers are explored for their mechanical and dielectric properties. An exploratory study by the author demonstrates the relationship between mechanical and dielectric properties for specimens obtained from a rotating mandrel horizontal setup.

Assembly of Well-Aligned Electrospun Nanofibers via Contact-Transfer Printing

2012 ◽  
Vol 562-564 ◽  
pp. 277-280
Author(s):  
Ling Zhi Liu ◽  
Yun Ze Long ◽  
Bin Sun ◽  
Hong Di Zhang ◽  
Pi Tao Dong ◽  
...  
Keyword(s):  
Large Scale ◽  
Electrospun Nanofibers ◽  
Practical Method ◽  
Electrospun Fibers ◽  
Flexible Substrates ◽  
Transfer Printing ◽  
Sio2 Substrate ◽  
Ordered Arrays ◽  
Aligned Nanofibers ◽  
High Degree

Electrospinning is a simple and practical method for fabricating uniform fibers with diameters range from several micrometers down to a few nanometers. In order to achieve highly ordered arrays of nanofibers, a novel and feasible approach, named contact-transfer printing of electrospun fibers, is reported in this paper. Via this method, large-scale aligned nanofibers on various rigid or flexible substrates can be assembled. This technique is demonstrated to be efficient on transferring of electrospun nanofibers with a high degree of alignment (~88.2%) on a SiO2 substrate. In addition, it is found that the printing outcome highly depends on the pressure between collecting and receiving substrate.

Effect of LiCl and non-ionic surfactant on morphology of polystyrene electrospun nanofibers

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Delaram Fallahi ◽  
Mehdi Rafizadeh ◽  
Naser Mohammadi ◽  
Behrooz Vahidi
Keyword(s):  
Electron Microscopy ◽  
Surface Tension ◽  
Electrospun Nanofibers ◽  
Average Diameter ◽  
Ionic Surfactant ◽  
Electrospun Fibers ◽  
Electrospinning Technique ◽  
Solution Surface ◽  
Solution Conductivity ◽  
Scanning Electron

AbstractPolystyrene fibers were produced by the electrospinning technique. The effects of solution conductivity, surface tension and concentration on morphology and average diameter of electrospun fibers were investigated by scanning electron microscopy (SEM). Solutions of 12, 10, 8, 6% (w/v) polystyrene in dimethylformamide were prepared. Lithium Chloride and a non-ionic surfactant were used to change the conductivity and surface tension of the solutions, respectively. The results indicate that increasing the solution conductivity eliminates the bead formation and increases the fiber diameters. By addition of salt, fine and consistent fibers could be produced from electrospinning of 8% (w/v) PS/DMF solution. Adding 0.1% surfactant reduces the solution surface tension and results in smaller beads and higher fiber diameters. By increasing the amount of surfactant to 0.3%, big beads and thinner fibers are produced.

scholarly journals Focused Patterning of Electrospun Nanofibers Using a Dielectric Guide Structure

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1505
Author(s):  
Byeongjun Lee ◽  
Younghyeon Song ◽  
Chan Park ◽  
Jungmin Kim ◽  
Jeongbeom Kang ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Finite Elements ◽  
Electric Field ◽  
Electrospun Nanofibers ◽  
Electrospun Fibers ◽  
Continuous Line ◽  
Key Factors ◽  
Key Technology ◽  
Vertical Electric Field ◽  
Dielectric Guide

The patterning of electrospun fibers is a key technology applicable to various fields. This study reports a novel focused patterning method for electrospun nanofibers that uses a cylindrical dielectric guide. The finite elements method (FEM) was used to analyze the electric field focusing phenomenon and ground its explanation in established theory. The horizontal and vertical electric field strengths in the simulation are shown to be key factors in determining the spatial distribution of nanofibers. The experimental results demonstrate a relationship between the size of the cylindrical dielectric guide and that of the electrospun area accumulated in the collector. By concentrating the electric field, we were able to fabricate a pattern of less than 6 mm. The demonstration of continuous line and square patterning shows that the electrospun area can be well controlled. This novel patterning method can be used in a variety of applications, such as sensors, biomedical devices, batteries, and composites.

scholarly journals Conformal Fabrication of an Electrospun Nanofiber Mat on a 3D Ear Cartilage-Shaped Hydrogel Collector Based on Hydrogel-Assisted Electrospinning

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jin Yeong Song ◽  
Hyun Il Ryu ◽  
Jeong Myeong Lee ◽  
Seong Hwan Bae ◽  
Jae Woo Lee ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Electrospun Nanofibers ◽  
Cell Delivery ◽  
Complex Geometries ◽  
Two Dimensional ◽  
Uniform Thickness ◽  
Electrospun Nanofiber ◽  
Electrospinning Technique ◽  
Ear Cartilage ◽  
Focused Electric Field

AbstractElectrospinning is a common and versatile process to produce nanofibers and deposit them on a collector as a two-dimensional nanofiber mat or a three-dimensional (3D) macroscopic arrangement. However, 3D electroconductive collectors with complex geometries, including protruded, curved, and recessed regions, generally caused hampering of a conformal deposition and incomplete covering of electrospun nanofibers. In this study, we suggested a conformal fabrication of an electrospun nanofiber mat on a 3D ear cartilage-shaped hydrogel collector based on hydrogel-assisted electrospinning. To relieve the influence of the complex geometries, we flattened the protruded parts of the 3D ear cartilage-shaped hydrogel collector by exploiting the flexibility of the hydrogel. We found that the suggested fabrication technique could significantly decrease an unevenly focused electric field, caused by the complex geometries of the 3D collector, by alleviating the standard deviation by more than 70% through numerical simulation. Furthermore, it was experimentally confirmed that an electrospun nanofiber mat conformally covered the flattened hydrogel collector with a uniform thickness, which was not achieved with the original hydrogel collector. Given that this study established the conformal electrospinning technique on 3D electroconductive collectors, it will contribute to various studies related to electrospinning, including tissue engineering, drug/cell delivery, environmental filter, and clothing.

Bone permittivity and its effect on using ground-penetrating radar

Geophysics ◽  
2018 ◽  
Vol 83 (1) ◽  
pp. H1-H11
Author(s):  
Blair B. Schneider ◽  
Georgios Tsoflias ◽  
Don W. Steeples ◽  
Rolfe Mandel ◽  
Jack Hofman
Keyword(s):  
Dielectric Properties ◽  
Dielectric Property ◽  
Ground Penetrating Radar ◽  
Relative Permittivity ◽  
Water Saturation ◽  
Mixing Models ◽  
Bone Properties ◽  
Animal Bone ◽  
Bone Minerals ◽  
Ground Penetrating

Ground-penetrating radar (GPR) is a powerful tool that is still being developed for archaeological investigations. We investigated the dielectric properties of mammoth bone and bone from modern bison, cow, deer, and elk as a proxy for applying GPR for detecting prehistoric animal remains. Sample dielectric properties (relative permittivity, loss factor, and loss-tangent values) were measured with an impedance analyzer over frequencies ranging from 10 MHz to 1 GHz. Bone-sample porosity, bulk density, water saturation, and volumetric water content of the specimens were also measured. The measured sample-relative permittivity values were then compared with modeled relative permittivity values using common dielectric-mixing models to determine which parameters control the best-fit predictions of relative permittivity of animal bone. We observe statistically significant dielectric-property differences among different animal fauna, as well as variation as a function of frequency. In addition, we determine that the relative permittivity values of 8–9 for similar minerals, such as apatite, are not suitable as a proxy for predicting animal bone properties. We estimate new relative permittivity values of 3–5 for dry animal bone minerals in the frequency range of 100–1000 MHz using these common dielectric-mixing models. We postulate that differences in bone microstructure contribute to dielectric-property variability.

Polymer nanofibers for biomedical applications: advances by electrospinning

2021 ◽  
Vol 04 ◽  
Author(s):  
Anna L.M.M. Toledo ◽  
Talita N. da Silva ◽  
Arianne C. dos S. Vaucher ◽  
Arthur H. V. Miranda ◽  
Gabriela C. C. Silva de Miranda ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
New Technologies ◽  
Low Cost ◽  
Electrospun Nanofibers ◽  
Delivery Systems ◽  
Electrospun Fibers ◽  
Sustained Delivery ◽  
Biomedical Devices ◽  
Ultrathin Fibers

Background: The demand for novel biomaterials has been exponentially rising in the last years as well as the searching for new technologies able to produce more efficient products in both drug delivery systems and regenerative medicine. Objective: The technique that can pretty well encompass the needs for novel and high-end materials with a relatively low-cost and easy operation is the electrospinning of polymer solutions. Methods: Electrospinning usually produces ultrathin fibers that can be applied in a myriad of biomedical devices including sustained delivery systems for drugs, proteins, biomolecules, hormones, etc that can be applied in a broad spectrum of applications, from transdermal patches to cancer-related drugs. Results: Electrospun fibers can be produced to mimic certain tissues of the human body, being an option to create new scaffolds for implants with several advantages. Conclusions: In this review, we aimed to encompass the use of electrospun fibers in the field of biomedical devices, more specifically in the use of electrospun nanofibers applications toward the production of drug delivery systems and scaffolds for tissue regeneration.

STAND-ALONE WATER TREATMENT: PERFORMANCE OF ELECTROSPUN NANOFIBERS

2016 ◽  
Vol 78 (12) ◽  
Author(s):  
A. Mataram ◽  
A. F. Ismail ◽  
E. Yuliwati ◽  
T. Matsuura ◽  
S. Rizal ◽  
...  
Keyword(s):  
Oxygen Demand ◽  
Electrospun Nanofibers ◽  
Water Filtration ◽  
Electrospinning Technique ◽  
Treatment Performance ◽  
Flat Sheet ◽  
Electrospun Membranes ◽  
Suspend Solid ◽  
Total Suspend Solid ◽  
Microfiltration Membranes

The aim of this study was to evaluate the use of nanofiber microfiltration membranes, spun by an innovative electrospinning technique, in water filtration applications. This study bridges between developments in electrospinning techniques for the production of flat sheet membranes and the application of these membranes in water filtration. The functionalized or non-functionalized for the removal of pathogens was investigated, in term of chemical oxygen demand, total suspend solid and ammonium in the waste water. Physical properties such as clean water permeability (CWP) and strength were also examined. The results showed a very good removal of TSS (range 94.83-97.34%), COD (89.32-95.27%) and NH3­-N (64.48-72.87%). These test showed that the electrospun membranes can be used for water filtration applications. 

scholarly journals Solvent Effects on Morphology and Electrical Properties of Poly(3-hexylthiophene) Electrospun Nanofibers

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1501 ◽  
Author(s):  
Jung-Yao Chen ◽  
Chien-You Su ◽  
Chau-Hsien Hsu ◽  
Yi-Hua Zhang ◽  
Qin-Cheng Zhang ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Field Effect Transistors ◽  
Electrospun Nanofibers ◽  
Charge Carrier Mobility ◽  
Organic Field Effect Transistors ◽  
Electrospun Nanofiber ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
The Core ◽  
Core Polymer

Herein, poly(3-hexylthiophene-2,5-diyl) (P3HT) nanofiber-based organic field-effect transistors were successfully prepared by coaxial electrospinning technique with P3HT as the core polymer and poly(methyl methacrylate) (PMMA) as the shell polymer, followed by extraction of PMMA. Three different solvents for the core polymer, including chloroform, chlorobenzene and 1,2,4-trichlorobenzene, were employed to manipulate the morphologies and electrical properties of P3HT electrospun nanofibers. Through the analyses from dynamic light scattering of P3HT solutions, polarized photoluminescence and X-ray diffraction pattern of P3HT electrospun nanofibers, it is revealed that the P3HT electrospun nanofiber prepared from the chloroform system displays a low crystallinity but highly oriented crystalline grains due to the dominant population of isolated-chain species in solution that greatly facilitates P3HT chain stretching during electrospinning. The resulting high charge-carrier mobility of 3.57 × 10−1 cm2·V−1·s−1 and decent mechanical deformation up to a strain of 80% make the P3HT electrospun nanofiber a promising means for fabricating stretchable optoelectronic devices.

Thermal Characterizations of HPMC/PVA Impregnated with CNC Electrospun Nanofibers

2020 ◽  
Vol 981 ◽  
pp. 115-120
Author(s):  
Etdal Bakhiet ◽  
Siti Fazira Samsudin ◽  
Farah Hanani Zulkifli ◽  
Aizi Nor Mazila Ramli
Keyword(s):  
Hydroxypropyl Methylcellulose ◽  
Electrospun Nanofibers ◽  
Maximum Temperature ◽  
Poly Vinyl Alcohol ◽  
Electrospun Nanofiber ◽  
Random Orientation ◽  
Electrospinning Technique ◽  
Peak Intensity ◽  
Major Weight Loss ◽  
Potential Applications

Interest in the nanotechnology invention has been increased among the researcher and industries which lead to many investigations and studies to develop a product with better performance. In this research, hydroxypropyl methylcellulose (HPMC) and poly (vinyl) alcohol (PVA) nanofiber with the ratio 1:1 and the concentration of 5 wt% and 7 wt%, respectively, were successfully fabricated by using electrospinning technique. The HPMC/ PVA was then blended with the different concentration of cellulose nanocrystal (CNC) at 2 wt%, 4 wt%, 6 wt% and 8 wt%. The SEM results of HPMC/PVA/CNC nanofibers shown random orientation fibers with average diameters of 62.28 nm - 252.80 nm. The TGA results showed three major weight loss that prove the decomposotion of HPMC/PVA/CNC was occured with three maximum temperature peaks around 69 °C, 290 °C and 392 °C. As for DSC, the peak intensity of the Tg in the electrospun nanofiber are decreasing as the concentration of CNCs increased might be due to the interfering of the CNC with the crystallization of the polymer causing mobility of the amorphous regions to be higher. Therefore, the study on the thermal properties of HPMC/PVA incorporated with CNCs nanofibers could be a reference for various potential applications.

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