ELECTROSTATIC CHARGE GENERATED FROM FABRICS SLIDING ON POLYMERIC MATERIALS

doi:10.21608/jest.2021.189766

“Dynamic” charging of polymers in the LVSEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100150186 ◽

1993 ◽

Vol 51 ◽

pp. 870-871

Author(s):

J. H. Butler ◽

D. C. Joy ◽

G. F. Bradley

Keyword(s):

Incident Beam ◽

Polymeric Materials ◽

Sample Surface ◽

Electrostatic Charge ◽

Objective Lens ◽

Insulating Materials ◽

Dynamic Charging ◽

The Subject ◽

Very High ◽

Immersion Type

Recently we have been using a field emission LVSEM with an immersion-type objective lens extensively for the examination of polymers at low (<2 keV) incident beam energies. During the course of these studies it became apparent that, even though operating in the vicinity of E2 (the accelerating voltage at which no electrostatic charge builds up on the sample surface), sample charging effects of a most curious nature do, in fact, abound.In general the LVSEM has been successful in producing a wealth of exciting information. However, when nonconducting polymers are the subject of observation at E2, an unexpected and unusual charge build-up behavior is almost always encountered on the sample surface under irradiation (c.f. Figure 1). Thus for strongly insulating materials, it is not as easy to work in the realm of E2 as earlier predicted. For example, in some polymeric materials, it appears that charging is a function of magnification: at very high magnifications the sample will charge "positively", at lower magnifications (with all other parameters the same) the same sample will charge negatively, and at even lower magnifications the same sample will revert back to a positive charging situation.

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The Resolution and Contrast in Biological Sections Determined by Inelastic and Elastic Scattering

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071569 ◽

1973 ◽

Vol 31 ◽

pp. 224-225

Author(s):

D. L. Misell

Keyword(s):

Electron Microscopy ◽

Adverse Effect ◽

Elastic Scattering ◽

Inelastic Scattering ◽

Amorphous Carbon ◽

Polymeric Materials ◽

Chromatic Aberration ◽

Image Resolution ◽

Quantitative Estimates ◽

Elastic Ratio

In the electron microscopy of biological sections the adverse effect of chromatic aberration on image resolution is well known. In this paper calculations are presented for the inelastic and elastic image intensities using a wave-optical formulation. Quantitative estimates of the deterioration in image resolution as a result of chromatic aberration are presented as an alternative to geometric calculations. The predominance of inelastic scattering in the unstained biological and polymeric materials is shown by the inelastic to elastic ratio, I/E, within an objective aperture of 0.005 rad for amorphous carbon of a thickness, t=50nm, typical of biological sections; E=200keV, I/E=16.

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Application Of Electron Microscopy To Automotive Finish Defect Analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134892 ◽

1990 ◽

Vol 48 (2) ◽

pp. 258-259

Author(s):

Martin J. Mahon ◽

Patrick W. Keating ◽

John T. McLaughlin

Keyword(s):

Electron Microscopy ◽

Zero Tolerance ◽

Polymeric Materials ◽

Plant Management ◽

Defect Analysis ◽

X Ray ◽

Root Cause ◽

Cutting Out ◽

Foreign Materials ◽

Automotive Finish

Coatings are applied to appliances, instruments and automobiles for a variety of reasons including corrosion protection and enhancement of market value. Automobile finishes are a highly complex blend of polymeric materials which have a definite impact on the eventual ability of a car to sell. Consumers report that the gloss of the finish is one of the major items they look for in an automobile.With the finish being such an important part of the automobile, there is a zero tolerance for paint defects by auto assembly plant management. Owing to the increased complexity of the paint matrix and its inability to be “forgiving” when foreign materials are introduced into a newly applied finish, the analysis of paint defects has taken on unparalleled importance. Scanning electron microscopy with its attendant x-ray analysis capability is the premier method of examining defects and attempting to identify their root cause.Defects are normally examined by cutting out a coupon sized portion of the autobody and viewing in an SEM at various angles.

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Problems with oxygen analysis in the system MgO-Al2O3-SiO2 with the electron microprobe

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100132753 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1624-1625

Author(s):

Michel Fialin ◽

Guy Rémond

Keyword(s):

Transition Metal ◽

Metal Oxides ◽

Transition Metal Oxides ◽

Electrostatic Charge ◽

Carbon Layer ◽

Sample Holder ◽

Rock Matrix ◽

Electrical Discharges ◽

Thin Carbon ◽

Beam Instabilities

Oxygen-bearing minerals are generally strong insulators (e.g. silicates), or if not (e.g. transition metal oxides), they are included within a rock matrix which electrically isolates them from the sample holder contacts. In this respect, a thin carbon layer (150 Å in our laboratory) is evaporated on the sections in order to restore the conductivity. For silicates, overestimated oxygen concentrations are usually noted when transition metal oxides are used as standards. These trends corroborate the results of Bastin and Heijligers on MgO, Al2O3 and SiO2. According to our experiments, these errors are independent of the accelerating voltage used (fig.l).Owing to the low density of preexisting defects within the Al2O3 single-crystal, no significant charge buildup occurs under irradiation at low accelerating voltage (< 10keV). As a consequence, neither beam instabilities, due to electrical discharges within the excited volume, nor losses of energy for beam electrons before striking the sample, due to the presence of the electrostatic charge-induced potential, are noted : measurements from both coated and uncoated samples give comparable results which demonstrates that the carbon coating is not the cause of the observed errors.

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Colloidal systems in soils

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168050 ◽

1994 ◽

Vol 52 ◽

pp. 64-65

Author(s):

J. Thieme ◽

J. Niemeyer ◽

P. Guttman

Keyword(s):

Clay Minerals ◽

Polymeric Materials ◽

Spatial Arrangement ◽

High Specific Surface Area ◽

Turnover Rates ◽

Colloidal Systems ◽

Chemical Conditions ◽

Aggregation Phenomena ◽

Iron And Manganese ◽

Soil Colloids

In soil science the fraction of colloids in soils is understood as particles with diameters smaller than 2μm. Clay minerals, aquoxides of iron and manganese, humic substances, and other polymeric materials are found in this fraction. The spatial arrangement (microstructure) is controlled by the substantial structure of the colloids, by the chemical composition of the soil solution, and by thesoil biota. This microstructure determines among other things the diffusive mass flow within the soils and as a result the availability of substances for chemical and microbiological reactions. The turnover of nutrients, the adsorption of toxicants and the weathering of soil clay minerals are examples of these surface mediated reactions. Due to their high specific surface area, the soil colloids are the most reactive species in this respect. Under the chemical conditions in soils, these minerals are associated in larger aggregates. The accessibility of reactive sites for these reactions on the surface of the colloids is reduced by this aggregation. To determine the turnover rates of chemicals within these aggregates it is highly desirable to visualize directly these aggregation phenomena.

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Lectin-Induced RBC Agglutination: Chemical vs. Cryofixation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600002920 ◽

1980 ◽

Vol 38 ◽

pp. 664-665

Author(s):

Dean A. Handley ◽

Lanping A. Sung ◽

Shu Chien

Keyword(s):

Lectin Binding ◽

Freeze Substitution ◽

Electrostatic Charge ◽

Geometric Parameters ◽

Comparative Approach ◽

Chemical Fixation ◽

Cell Surfaces ◽

Minimal Cell ◽

Membrane Stiffness ◽

Cell Contour

RBC agglutination by lectins represents an interactive balance between the attractive (bridging) force due to lectin binding on cell surfaces and disaggregating forces, such as membrane stiffness and electrostatic charge repulsion (1). During agglutination, critical geometric parameters of cell contour and intercellular distance reflect the magnitude of these interactive forces and the size of the bridging macromolecule (2). Valid ultrastructural measurements of these geometric parameters from agglutinated RBC's require preservation with minimal cell distortion. As chemical fixation may adversely influence RBC geometric properties (3), we used chemical fixation and cryofixation (rapid freezing followed by freeze-substitution) as a comparative approach to examine these parameters from RBC agglutinated with Ulex I lectin.

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Pyridyl disulfide-based thiol–disulfide exchange reaction: shaping the design of redox-responsive polymeric materials

Polymer Chemistry ◽

10.1039/d0py01215g ◽

2020 ◽

Vol 11 (48) ◽

pp. 7603-7624

Author(s):

Ismail Altinbasak ◽

Mehmet Arslan ◽

Rana Sanyal ◽

Amitav Sanyal

Keyword(s):

Exchange Reaction ◽

Functional Materials ◽

Polymeric Materials ◽

Disulfide Exchange ◽

Redox Responsive ◽

Synthetic Approaches

This review provides an overview of synthetic approaches utilized to incorporate the thiol-reactive pyridyl-disulfide motif into various polymeric materials, and briefly highlights its utilization to obtain functional materials.

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