AFM, LVHRSEM, and cross-sectional TEM of the near-surface morphology of diblock copolymers

1992 ◽  
Vol 50 (2) ◽  
pp. 1032-1033
Author(s):  
D. W. Schwark ◽  
D. L. Vezie ◽  
J. R. Reffner ◽  
E. L. Thomas ◽  
B. K. Annis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Diblock Copolymers ◽  
Surface Composition ◽  
Low Voltage ◽  
Complete Characterization ◽  
Cross Sectional ◽  
Near Surface ◽  
Microscopy Technique ◽  
Self Assembling ◽  
Microscopy Techniques

Application of block copolymers as adhesives and biomedical devices requires an understanding of the surface composition and morphology of these materials. Microscopy techniques offer excellent depth and lateral resolution and therefore can provide direct microstructural and compositional surface data. Previous workers frequently used only a single microscopy technique to investigate the influence of an external surface constraint on the morphology. The implementation of several different microscopy techniques, each with its own strengths, affords a very complete characterization of the surface composition and morphology of self-assembling diblock copolymers.The investigation of solvent-cast and annealed thick (1 mm) films of two poly(styrene-b-butadiene) (SB) diblock copolymers, which usually self-assemble to form alternating poly(styrene) (PS) and poly (butadiene) (PB) lamellar microdomains, by three complementary microscopy techniques: cross-sectional transmission electron microscopy (CSTEM), low-voltage high-resolution scanning electron microscopy (LVHRSEM), and atomic force microscopy (AFM) is discussed. For CSTEM and LVHRSEM imaging, contrast between the PS and PB phases was enhanced by preferential staining of the PB phase with the vapors of a 4% aqueous osmium-tetroxide (OsO4) solution for 24 hours.

scholarly journals High Resolution Transmission Electron Microscopy of Metallic Film/Laser-Irradiated Alumina Couples.

1994 ◽  
Vol 357 ◽  
Author(s):  
A. J. Pedraza ◽  
Siqi Cao ◽  
L. F. Allard ◽  
D. H. Lowndes
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Copper Film ◽  
Interfacial Structure ◽  
Diffuse Interface ◽  
Cross Sectional ◽  
Polycrystalline Alumina ◽  
Near Surface ◽  
Transmission Electron

AbstractA near-surface thin layer is melted when single crystal alumina (sapphire) is pulsed laserirradiated in an Ar-4%H2 atmosphere. γ-alumina grows epitaxially from the (0001) face of axalumina (sapphire) during the rapid solidification of this layer that occurs once the laser pulse is over. Cross sectional high resolution transmission electron microscopy (HRTEM) reveals that the interface between unmelted sapphire and γ-alumina is atomistically flat with steps of one to a few close-packed oxygen layers; however, pronounced lattice distortions exist in the resolidified γ-alumina. HRTEM also is used to study the metal-ceramic interface of a copper film deposited on a laser-irradiated alumina substrate. The observed changes of the interfacial structure relative to that of unexposed substrates are correlated with the strong enhancement of film-substrate bonding promoted by laser irradiation. HRTEM shows that a thin amorphous film is produced after irradiation of 99.6% polycrystalline alumina. Formation of a diffuse interface and atomic rearrangements that can take place in metastable phases contribute to enhance the bonding strength of copper to laser-irradiated alumina.

Field Emission Scanning Electron Microscopy Studies of Industrial Polymers - A Survey

1998 ◽  
Vol 4 (S2) ◽  
pp. 814-815
Author(s):  
E.F. Osten ◽  
M.S. Smith
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Field Emission ◽  
Low Voltage ◽  
Structural Features ◽  
X Ray Diffraction ◽  
Styrene Acrylonitrile ◽  
Microscopy Techniques ◽  
Scanning Electron

We are using the term "Industrial Polymers" to refer to polymers [plastics] that are produced by the ton or (in the case of films) by the mile. For example, in descending order of world-wide use (tonnage), the top eight of these polymers are polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), styrene polymers (including polystyrene - PS, and acrylonitrile-butadienestyrene/ styrene-acrylonitrile - ABS/SAN), polyesters (PETP), polyurethane (PU), phenolics and aminoplastics.Industrial polymers, which have been produced by the millions of tons for the last five decades and are of obvious social and economic importance, have been exhaustively characterized. Structural features which affect physical properties and indicate process variables have been studied by many techniques other than microscopy (x-ray diffraction, thermal analysis, rheology, chromatographies, etc.). Microscopy techniques for polymer characterization have been well documented. Our motivation to apply field emission (high resolution) scanning electron microscopy to the study of polymers is: (1) The application of low voltage, high resolution SEM to biological materials is well characterized.

Sputtering Effects and Two Dimensional Arrangement of Nanoparticles in Insulators Under High Flux Cu Implantation

1999 ◽  
Vol 581 ◽  
Author(s):  
N. Kishimoto ◽  
C.G. Lee ◽  
N. Umeda ◽  
Y. Takeda ◽  
V.T. Gritsyna
Keyword(s):  
Dose Rate ◽  
High Flux ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Near Surface ◽  
Self Assembling ◽  
Surface Nanostructures ◽  
Radiation Induced ◽  
High Doses ◽  
Surface Sputtering

ABSTRACTApplication of negative heavy ions, alleviating surface charging on insulators, enables us to conduct low-energy and high-flux implantation, and leads to a well-defined tool to fabricate near-surface nanostructures. Negative Cu ions of 60 keV, at high doses, have generated nanocrystals in amorphous(a-)SiO2 with a size (∼10 nm) suitable for nonlinear optical devices. The kinetic processes, inside the solid and at the surface, are studied by cross-sectional TEM and tapping AFM, respectively. In a-SiO2, nanoparticles spontaneously grow with dose rate, being controlled by the surface tension and radiation-induced diffusion. Furthermore, the nanospheres give rise to a two-dimensional (2D) arrangement around a given dose rate. The 2D-distribution occurs in coincidence with enhanced sputtering where a considerable Cu fraction sublimates from the surface. The dose-rate dependence of nanoparticles indicates that the surface-sputtering process influences the intra-solid process and contributes to the 2D-distribution. A self-assembling mechanism for 2D-arrangement of nanospheres is discussed taking into account contribution of the surface sputtering.

Correlative microscopy techniques for material science

1995 ◽  
Vol 53 ◽  
pp. 688-689
Author(s):  
J.S. Hudson
Keyword(s):  
Electron Microscopy ◽  
Material Science ◽  
Computer Network ◽  
Network System ◽  
Correlative Microscopy ◽  
Clemson University ◽  
Advantages And Disadvantages ◽  
Microscopy Technique ◽  
Multiple Data ◽  
Microscopy Techniques

The microscopy center at Clemson University recently invested funds to provide a computer network system that incorporates all of its microscopes. The facility connects SEM, TEM, STM/AFM, Auger Microprobe and the light microscope to Sun workstations equipped with chemical analysis and imaging programs. Images from the network system microscopes can be sent to any of the workstations. I should like to review a few applications of correlative microscopy techniques related to material science; this is a technology that allows the acquisition of multiple data from a given sample. Often a given technique can be augmented by the use of complimentary microscopy technique. Since electron microscopy is subject to interpretation, correlative microscopy methods will prove to be useful in reaching conclusions regarding the image micrographs. Additionally, more than one type of information may be necessary for a given material and this can be found with the different systems of microscopy. In my presentation I will discuss instrumentation and methods by demonstrating advantages and disadvantages of applications as they apply to materials such as polymers, ceramics, microstructures and textiles.

Application of low-voltage Scanning Electron Microscopy to studies of polymer near-surface diffusion and hydrophobicity

1990 ◽  
Vol 48 (4) ◽  
pp. 1108-1109
Author(s):  
J. Chang ◽  
s. Krause ◽  
R. Gorur
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Molecular Diffusion ◽  
Low Voltage ◽  
Analytical Techniques ◽  
Surface Characteristics ◽  
Recovery Process ◽  
Near Surface ◽  
Voltage Scanning ◽  
Scanning Electron

The study of the surface characteristics of a polymeric insulator - such as silicone rubber (SR) and ethylene propylene diene monomer (EPDM) -- is necessary to understand the hydrophobicity recovery mechanism that governs the ability of insulators to withstand electrical stresses during high voltage service. It has been shown that hydrophobicity of a polymeric insulator surface could be reduced by electrical discharges during outdoor service, causing the surface to become wettable, and thus allow water films to form, and ultimately leading to power outages. It was also reported that the recovery process could be due to the diffusion of low molecular weight (LMW) polymer chains from the bulk of the material to the surface. Because the LMW chains are in fluidic form (oil), they are able to diffuse through the material due to the concentration gradient of these species between the bulk and the surface. The exact mechanism of hydrophobicity recovery in polymeric insulators is still not well understood. In this study, an investigation was conducted to examine the effects of near surface molecular diffusion in the hydrophobicity recovery process of SR and EPDM insulators. Different analytical techniques were used to examine the surface morphology and surface charging effects of these elastomeric materials. Low voltage scanning electron microscopy (LVSEM) was used to measure the second cross-over point (E2) of the material surfaces, and electron spectroscopy for chemical analysis (ESCA) was also used to identify the surface chemical composition.

Diagnostics for Assessing Spectral Quality for X-Ray Microanalysis in Low Voltage and Variable Pressure Scanning Electron Microscopy

2001 ◽  
Vol 7 (S2) ◽  
pp. 702-703
Author(s):  
Dale E. Newbury
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Voltage ◽  
Operating Conditions ◽  
Variable Pressure ◽  
X Ray ◽  
Operating Modes ◽  
Surface Charging ◽  
Microscopy Techniques ◽  
Scanning Electron

There is increasing interest in performing x-ray microanalysis of uncoated insulators while operating in unconventional SEM operating modes such as “low voltage” scanning electron microscopy (LVSEM), where the accelerating voltage is ≤ 5 kV and the pressure is low (<10-4 Pa), or variable pressure environmental SEM (VP-ESEM), where a selected gas is maintained at pressures in the range of 1 Pa -1000 Pa. LVSEM and VP-ESEM as microscopy techniques have proven to be extremely successful for imaging uncoated insulators through various charge dissipation mechanisms that are not available under conventional SEM operating conditions (accelerating voltage ≥ 10 kV and pressure < 10-3 Pa). in LVSEM, surface charging of insulators can often be controlled by careful choice of the accelerating voltage, sample tilt, and scan rate, while in VP-ESEM the charged species in the relatively dense gas (ions, secondary electrons) form a self-neutralizing plasma to provide an additional route for discharging the specimen.

A transmission electron microscopy investigation of sulfide nanocrystals formed by ion implantation

1999 ◽  
Vol 14 (12) ◽  
pp. 4489-4502 ◽  
Author(s):  
A. Meldrum ◽  
E. Sonder ◽  
R. A. Zuhr ◽  
I. M. Anderson ◽  
J. D. Budai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Implantation ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Microscopy Investigation ◽  
Electron Microscopy Investigation ◽  
Concentration Of Ions ◽  
Form Compound ◽  
Microscopy Techniques

Ion implantation was used to form compound semiconductor nanocrystal precipitates of ZnS, CdS, and PbS in both glass and crystalline matrices. The precipitate microstructures and size distributions were investigated by cross-sectional transmission electron microscopy techniques. Several unusual features were observed, including strongly depth-dependent size variations of the ZnS precipitates and central void features in the CdS nanocrystals. The morphology and crystal structure of the nanocrystal precipitates could be controlled by selection of the host material. The size distribution and microstructural complexity were significantly reduced by implanting a low concentration of ions into a noncrystalline host, and by using multi-energy implants to give a flat concentration profile of the implanted elements.

Study on End-of-Range Defects Induced by Sb Implantation

2003 ◽  
Vol 792 ◽  
Author(s):  
Yi-Sheng Lai ◽  
J. S. Chen ◽  
Y. S. Ho ◽  
H. L. Sun ◽  
K. B. Huang
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Solid Phase ◽  
Threshold Energy ◽  
Extended Defects ◽  
Cross Sectional ◽  
Near Surface ◽  
Spike Annealing ◽  
Secondary Ion ◽  
Post Implantation

ABSTRACTExtended defects formed by antimony ion implantation in Si(100) was investigated as a function of the implant energy. The implanted layer was examined by cross-sectional electron microscopy (TEM). Post-implantation spike-annealing was also performed from 950°C to 1095°C to examine evolution of defects. From the TEM study, the threshold energy to induce visible defects for Sb implantation was found to be more than 50 keV. A mapping for the location of defects was constructed by TEM and secondary ion mass spectroscopy (SIMS). The end-of-range (EOR) defects, which were possibly formed during the solid phase epitaixy regrowth, were located near the lower bound of the transition region. For 70-keV implantation, extended defects appear at the near-surface and the EOR region. It was observed that the near-surface defects diminished after annealing at more than 1050°C, while the EOR defects became coarsening at 1095°C.

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