scholarly journals Effects of Jet Path on Electrospun Polystyrene Fibers

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 842 ◽  
Author(s):  
Yuansheng Zheng ◽  
Na Meng ◽  
Binjie Xin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Morphology ◽  
High Speed ◽  
Solution Concentration ◽  
Electrospinning Process ◽  
High Speed Photography ◽  
Fiber Mats ◽  
Jet Length ◽  
Scanning Electron

In this study we investigated the effects of jet path on the morphology and mat size of synthetic polystyrene (PS) fibers during the electrospinning process. In addition, the mechanism of the fiber mats, which were prepared by varying the solution concentration, was evaluated. The straight jet length, envelope cone and whipping frequency of each electrospun jet were studied using images captured by a high-speed photography camera. The results showed that higher solution concentrations led to longer straight jet lengths, smaller envelope cones and lower whipping frequencies. The diameter and surface morphology of the PS fibers were also characterized by scanning electron microscopy (SEM). It was found that fibers spun with higher solution concentrations exhibited larger diameters and diameter distributions because of their jet path features. Furthermore, the electrospun jets with higher concentrations increased elongation and produced smaller fiber mats and higher breaking forces as a result of their different jet paths, which was a consequence of varying the solution concentration.

Study on PS-Molybdophosphoric Composite Fibers via Electrospinning Process

2013 ◽  
Vol 750-752 ◽  
pp. 311-314
Author(s):  
Zhi Ming Zhang ◽  
Ting Ting Li ◽  
Jie Cao ◽  
He Ti Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Morphology ◽  
Composite Membrane ◽  
Hot Pressing ◽  
Electrospinning Process ◽  
Molybdophosphoric Acid ◽  
Composite Fibers ◽  
Cold Pressing ◽  
Scanning Electron

Fine polystyrene fibers have been generated from electrospinning of PS/molybdophosphoric acid in THF and DMF solution. The fiber diameters ranged from 500 nm and increased by adjusting the volume of DMF, the amount of the PS/ molybdophosphoric acid and spinning voltage, the size of the distance. Surface morphology of the nanofibers was characterized by scanning electron microscopy (SEM). The fibers generated from the solutions were more homogeneous in sizes, especially when more THF was added. With the phosphomolybdate amount of increase in untreated, cold pressing, hot pressing modulus showed a trend to decrease. The infrared results show that the composite membrane contains four phosphomolybdate absorption peaks, which is consistent with the predicted results.

Morphology of Biodegradable Poly(hexamethylene Adipate)(PHMA) Nanofibers Prepared by Electrospinning

2009 ◽  
Vol 87-88 ◽  
pp. 555-560
Author(s):  
Wei Min Kang ◽  
Bo Wen Cheng ◽  
Quan Xiang Li ◽  
Xu Pin Zhuang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Flow Rate ◽  
Applied Voltage ◽  
Mixed Solvent ◽  
Solution Concentration ◽  
Electrospinning Process ◽  
Solvent Ratio ◽  
Biodegradable Poly ◽  
Scanning Electron

A kind of novel biodegradable poly(hexamethylene adipate) (PHMA) nanofibers with diameter of 100～700nm using a mixed solvent of 1,2-dichloroethane (DCE ) and trifluoroacetic acid (TFA) were obtained by electrospinning process in this paper. The morphology of electropun PHMA nanofibers were investigated by scanning electron microscopy (SEM). The results showed that the morphology, diameter and uniformity of the fibers were influenced by solvent ratio, solution concentration, applied voltage, capillary–screen distance and flow rate greatly. The finer and uniform nanofibers were electrospun from a mixed solvent of DCE and TFA with ratio of 70/30(w/w).

The erosion and deformation of polyethylene by solid-particle impact

1987 ◽  
Vol 321 (1558) ◽  
pp. 277-303 ◽  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mass Loss ◽  
Solid Particle ◽  
High Speed ◽  
Particle Impact ◽  
High Speed Photography ◽  
Flux Rate ◽  
Steel Sphere ◽  
Scanning Electron

In recent years, polyethylene (PE) has found increasing use in applications involving impact and erosion. This paper describes a detailed study of the properties of PE subjected to solid particle impact. Flat discs of the material were eroded by sieved sand (300-600 pm) accelerated by using an air blast rig in which the important variables of velocity, angle and mass flux rate are accurately controllable and measurable. Scanning electron microscopy of lightly eroded specimens enabled four basic crater types to be identified: smooth, ploughed, cut, and dented. The proportions of each were established over a range of angles. Long time erosion experiments were conducted in which the flux rate for each angle was adjusted to keep the number of impacts per unit time constant. The dimensionless erosion parameter, e (mass lost per unit mass of erodent that has struck) was computed by using the rate of mass loss when steady-state erosion had been established. Most erosion was found to occur at an angle of 20—30°, the mass loss becoming zero at around 80°. An analysis by D. R. Andrews is presented, showing that the flux rates used in these experiments are well below those needed to cause wear by thermal mechanisms, and this was confirmed by changing the flux rate: mass loss increased in proportion. Macroscopic particles were used to model sand grain impacts, spheres for rounded particles and square plates for sharp ones. A range of techniques was used in this study including high-speed photography (framing speed of 5 x 10 4 s -1 ), scanning electron microscopy, and moire methods (both in-plane and out-of-plane). A deformation map was constructed for steel sphere im pacts giving the type of crater to be expected at a given angle and speed. It was observed that sand grains required much lower speeds at a given angle to produce a given crater type. High-speed photography enabled mass-loss mechanisms for single-particle impact to be identified. These were the drawing-out of filaments and the machining-out of chips. Quantitative data on kinetic energy losses were obtained, and these, combined with moire methods that gave the sizes of deformed zones, enabled an estimate of the temperature rise per impact to be made (25 K).

The Formation and Morphology of PVA Ferrogel Nanofibre by the Electrospinning Process

2010 ◽  
Vol 650 ◽  
pp. 361-366 ◽  
Author(s):  
Tao Yu Wan ◽  
Mohammad Chowdhury ◽  
George K. Stylios
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Polyvinyl Alcohol ◽  
Flow Rate ◽  
Electrospinning Process ◽  
Magnetic Sensors ◽  
Solution Flow Rate ◽  
Solution Flow ◽  
Fiber Mats ◽  
Scanning Electron

Aqueous solutions of polyvinyl alcohol (PVA) with FeCl3 were homogenously mixed and subsequently electrospun; and its characteristics were studied as a function of voltage, tip-target distance and solution flow rate. Fiber mats of (PVA)/FeCl3 composite, in the diameter of 700–1100 nm were prepared by electrospinning. Lower concentrations of solution tended to facilitate the formation of fibres with beads. With increasing concentration, the morphology was improved with smooth and uniform fibres and the increased fibre diameters in the nano range. Spinning voltage also had an important influence on the diameters of the nano fibres, while the collection distance affected fibre diameters. Nano fibres of smaller diameter were formed when lower voltages are applied. The morphology of the electrospun from PVA/FeCl3 nano fibres and their magnetic power was observed and analyzed by scanning electron microscopy (SEM).The fibres produced in this way could potentially be applied to manufacture magnetic sensors, flexible magnets.

The bright future of digital imaging in scanning electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 768-769
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Digital Imaging ◽  
High Speed ◽  
High Performance ◽  
Mass Storage ◽  
Analog To Digital ◽  
Central Processing ◽  
Digital Imaging Technology ◽  
Scanning Electron

One of the major advancements applied to scanning electron microscopy (SEM) during the past 10 years has been the development and application of digital imaging technology. Advancements in technology, notably the availability of less expensive, high-density memory chips and the development of high speed analog-to-digital converters, mass storage and high performance central processing units have fostered this revolution. Today, most modern SEM instruments have digital electronics as a standard feature. These instruments, generally have 8 bit or 256 gray levels with, at least, 512 × 512 pixel density operating at TV rate. In addition, current slow-scan commercial frame-grabber cards, directly applicable to the SEM, can have upwards of 12-14 bit lateral resolution permitting image acquisition at 4096 × 4096 resolution or greater. The two major categories of SEM systems to which digital technology have been applied are:In the analog SEM system the scan generator is normally operated in an analog manner and the image is displayed in an analog or "slow scan" mode.

Spin-polarized Scanning Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 768-769
Author(s):  
Kazuyuki Koike ◽  
Hideo Matsuyama
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Speed ◽  
Magnetic Thin Films ◽  
Electron Spin Polarization ◽  
Acquisition Time ◽  
Magnetization Direction ◽  
Spin Polarized ◽  
Conventional Methods ◽  
Scanning Electron

Spin-polarized scanning electron microscopy (spin SEM), where the secondary electron spin polarization is used as the image signal, is a novel technique for magnetic domain observation. Since its first development by Koike and Hayakawa in 1984, several laboratories have extensively studied this technique and have greatly improved its capability for data extraction and its range of applications. This paper reviews the progress over the last few years.Almost all the high expectations initially held for spin SEM have been realized. A spatial resolution of several hundreds angstroms has been attained, which is nearly one order of magnitude higher than that of conventional methods for thick samples. Quantitative analysis of magnetization direction has been performed more easily than with conventional methods. Domain observation of the surface of three-dimensional samples has been confirmed to be possible. One of the drawbacks, a long image acquisition time, has been eased by combining highspeed image-signal processing with high speed scanning, although at the cost of image quality. By using spin SEM, the magnetic structure of a 180 degrees surface Neel wall, magnetic thin films, multilayered films, magnetic discs, etc., have been investigated.

Isolasi Dan Karakterisasi Bentonit Alam Menjadi Nanopartikel Monmorillonit

2018 ◽  
Vol 3 (1) ◽  
pp. 12 ◽  
Author(s):  
Zaimahwati Zaimahwati ◽  
Yuniati Yuniati ◽  
Ramzi Jalal ◽  
Syahman Zhafiri ◽  
Yuli Yetri
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Surface Morphology ◽  
Average Diameter ◽  
Particle Size Analyzer ◽  
Ft Ir ◽  
Scanning Electron ◽  
Sedimentation Processes

<p>Pada penelitian ini telah dilakukan isolasi dan karakterisasi bentonit alam menjadi nanopartikel montmorillonit. Bentonit alam yang digunakan diambil dari desa Blangdalam, Kecamatan Nisam Kabupaten Aceh Utara.  Proses isolasi meliputi proses pelarutan dengan aquades, ultrasonic dan proses sedimentasi. Untuk mengetahui karakterisasi montmorillonit dilakukan uji FT-IR, X-RD dan uji morfologi permukaan dengan Scanning Electron Microscopy (SEM). Partikel size analyzer untuk menganalisis dan menentukan ukuran nanopartikel dari isolasi bentonit alam. Dari hasil penelitian didapat ukuran nanopartikel montmorillonit hasil isolasi dari bentonit alam diperoleh berdiameter rata-rata 82,15 nm.</p><p><em>In this research we have isolated and characterized natural bentonite into montmorillonite nanoparticles. Natural bentonite used was taken from Blangdalam village, Nisam sub-district, North Aceh district. The isolation process includes dissolving process with aquades, ultrasonic and sedimentation processes.  The characterization of montmorillonite, FT-IR, X-RD and surface morphology test by Scanning Electron Microscopy (SEM). Particle size analyzer to analyze and determine the size of nanoparticles from natural bentonite insulation. From the research results obtained the size of montmorillonite nanoparticles isolated from natural bentonite obtained an average diameter of 82.15 nm.</em></p>

Deposition of Polypyrrole Onto a Novel Polymer Electrode for Use in a Biomimetic Artificial Excitable Cell Membrane

2010 ◽  
Author(s):  
Christina V. Haden ◽  
Donald A. Jordan ◽  
Pamela M. Norris
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Membrane ◽  
Surface Morphology ◽  
Polymer Membrane ◽  
Electroactive Polymer ◽  
Gating System ◽  
Excitable Cell ◽  
Semi Solid ◽  
Scanning Electron

A novel and inexpensive bucky gel electrode has been investigated for use as the electrode substrate for deposition of polypyrrole. The electroactive polymer membrane was successfully deposited and the surface morphology studied using scanning electron microscopy. Given the properties of the bucky gel electrode and its ability to conduct ions, this work establishes the first step towards a semi-solid ion-gating system to be used in further applications.

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