Silicone materials may be incorporated into organic thermoplastic resins to provide enhanced properties. Good dispersion of silicone with plastics is believed to be one of the keys to control the applications of these multiphase blends. In this study, we investigated the morphologies of mechanically mixed silicone/organic blends using scanning electron microscopy (SEM). Results provide an important piece of information that the optimum silicone phase dispersion can be achieved by matching the viscosities of the blend components.

Most silicone and organic polymers are thermodynamically immiscible, forming multiphase structures for their blends. For example, a blend consisting of 90 wt% polydimethylsiloxane (PDMS) and 10% low density polyethylene (LDPE) was revealed by SEM to have a multiphase structure shown in Figure 1A where the PDMS was a Dow Corning® 3-5016 silanol-terminated siloxane fluid that forms the dispersed phase and the LDPE a Dow Chemical polyethylene having a melt index of 4.

Plant fibers such as cotton, hemp and flax have been cultivated for textile purposes for thousands of years. These natural fibers play an important role in daily life as apparel fibers since they provide unique comfort properties unsurpassed by synthetic fibers. However, their use is not limited to the apparel sector. In recent years the market share of consumer textiles and industrial products made from all kinds of natural fibers has tremendously increased as they present a valuable source of renewable raw materials. Investigating their surface features by microscopic techniques is important to control the performance of the desired end-product. Processing steps involving heat, light or exposure to chemicals might have a significant impact on the specific surface properties of a fiber whether or not this was originally intended. Scanning electron microscopy is therefore a very useful tool for the characterization of textile products to determine the effectiveness and eventual resulting damage from physical or chemical treatments.

Natural fibers generally lack uniformity and large numbers of measurements often must be obtained to achieve estimates of sample parameters having reasonable levels of precision and confidence. This problem calls for automating the measurement and data analysis processes so obtaining a large amount of data is practical. We will discuss hardware and software designs used in our laboratory to automate microscope measurements and data analysis for fibrous materials.

Automating the measuring process requires constructing hardware to accomplish several tasks. Hardware should accommodate large-sized samples when they lack uniformity since many measurements are desirable. Sample positioning should be automated to remove the operator from the data acquisition process and eliminate a source of operator-dependent positioning error. Lens focusing should be automated since it is difficult to maintain flatness for large samples and the thickness of many samples exceeds the depth-of-focus of lenses. Finally, the quality of illumination provided to all sample locations during measurement should be flexible and consistent.

Single fiber fracture is important in understanding the fundamental failure mechanisms in wood/polymer composite products such as medium density fiberboard (MDF). The mechanical properties and fracture behavior of individual wood fibers has only recently been observable using a combination of environmental scanning electron microscopy (ESEM), laser scanning confocal microscopy and digital image correlation (DIC). Previous work has shown that specific areas on the fiber such as microcompressions and pits acted as crack nucelators and induce a brash fracture across the surface of the fiber. Given the development of these procedures it is now possible to observe and measure the mechanical properties and fracture characteristics of the wood fiber/ polymer composite fibers.

Individual black spruce wood fibers were coated with diphenylmethane 4-4'diisocyanate resin containing Hostasol Red GG. The addition of the Hostasol Red flurochrome provided the option of quantifying resin coverage by fluorescence microscopy.

Cotton is the single most economically important natural textile fiber in the world. It is a seed hair and has historically composed a large portion of the world's textiles. The plant is grown in most tropical and subtropical regions of the world. The demand for cotton, especially as a garment fiber, it due to properties such as its soft hand, water absorption, spinnability, and dyeability, and to its ease of home laundering. Perhaps cotton's most important textile property is its comfort. These properties are due to the unique, multilayered construction of the fiber subunits. The nature of this construction has been studied microscopically for more than 100 years, first using light microscopes, then electron microscopes as they became available. Because they are natural biological materials, no two cotton fibers are exactly alike. Yet they do have certain structural features in common. Structure in cotton can refer to several levels of construction.

Microscopical procedures for the evaluation of cotton textiles are important to the textile industry in evaluating mixed fiber blends, dyes and chemical finishes on fabrics. A new procedure for embedding cellulosic textiles has been developed for FT-IR microscopy whereby fibers are embedded in polystyrene. This polymer does not absorb in the same regions of the infrared spectrum as cellulose or traditional acrylate and epoxy resins that contain chemical groups in common with cellulose. Additionally, use of cross-sections mounted on a KBr disk (Fig. 1) has the advantage of better resolution (Fig. 2B) than grinding and pressing fibers in a KBr disk (Fig. 2A).

A new process for the evaluation of yarns has been developed. Approximately 2000 fibers before spinning, 50 yarn segments after spinning, or yarns removed from fabric after processing, can be encased in a tube, embedded in methacrylate plastic, quickly UV polymerized, and sectioned.

Multiple microspectroscopic imaging techniques have been employed to reveal the chemical and structural nature of flax (Linum usitatissimum L.) stem tissue, with the goal of finding the best technique by which to monitor retting processes for the production of linen fibers. Three of these techniques, which we have investigated for this purpose, are: mid-infrared (MIR), Raman and nuclear magnetic resonance (NMR) imaging. Initially, all three techniques were evaluated on the basis of their ability to reveal the nature of unretted flax stems. MIR imaging was found to be the most useful for this purpose. Thus, it was selected as the method of choice to follow retting processes to obtain flax fibers.

A Fourier transform (FT)-IR spectrometer equipped with microscope was used to acquire the MTR images. A FT-Raman spectrometer that was equipped with a Raman microprobe and utilizing a 1064 nm laser source was used to collect the Raman images.

Flax (Linum usitatissimum L.) and kenaf (Hibiscus cannabinus L.) are the sources of fibers used for textiles and other industrial applications. Both flax and kenaf produce fibers in the bast region (Fig. 1, 2) which must be separated from other tissues by retting. Although both flax and kenaf are bast fibers, their properties are vastly different. UV absorption microspectrophotometry and histochemistry elucidate their chemistry and structure related to enzymatic retting.

Aromatics such as lignins are produced by plants for protection and strength, but their presence inhibits microbial degradation, which is necessary in retting. Histochemical tests indicated variations in the site and type of aromatics within these two plants (1,2). In flax, acid phloroglucinol but not chlorine-sulfite gave positive reactions occasionally in fiber cell walls in the bast. The other cell walls in the bast did not contain aromatics by these tests, although aromatics occurred in the cuticle.

Porous nylon fabric is used as a filter in blood devices. This study was undertaken to evaluate the interaction between an experimental nylon filter and the cellular elements which pass through it. Our investigation was mainly centered on determining the deposition of cellular material on the nylon filter using Low Voltage Scanning Electron Microscopy (LVSEM) and Transmission Electron Microscopy (TEM).

The filter was prepared for LVSEM by cutting a 2.5 cm2 of the nylon filter material with a razor and placing it in a nylon mesh bag which was stapled shut. The bag was rinsed three times for ten minutes each in fresh Sorensen's phosphate buffer. A graded alcohol series of 25%, 35%, 50%, 70%, 80%, and 90% was used to dehydrate the filter for ten minutes each. This was followed by dehydration twice for 20 minutes in fresh 100% ETOH. The filter was then Critical Point Dried (CPD) in the Tousimis AUTOSAMDRI-814.

A Cryosorption Freeze Drying (CFD) system was evaluated for its effectiveness in preparing delicate biological materials for both low voltage-field emission scanning electron microscopy (LVFESEM) and imaging liquid metal (Ga) ion beam, static time-of-flight, secondary ion mass spectrometry (TOF-SIMS). The primary goals of these studies were to investigate the retention of both structural and chemical integrity using fresh cryoprepared biological material which had not been exposed to any chemical fixation and which would not be coated by any conductive material in order to obtain information from the native surfaces. Duplicate chemically fixed samples were processed for comparison. LV-FESEM (2-2.5kV) was used to assess the quality of the structural preservation of the freezing and freeze drying (FD) protocols. Imaging static TOF-SIMS was used to investigate the surface chemical compositions of the biological samples.

The extraction of lipids and phospholipids during dehydration and plastic embedding steps results in poor preservation of the phospholipid rich lamellar bodies (LB) in alveolar type II epithelial cells. To achieve better retention of phospholipids, we combined inflation fixation and an en bloc staining protocol using 4% aqueous uranyl acetate (UA), thereby improving the preservation of the LBs for both the wild type and transgenic mice expressing modified pulmonary surfactant protein B (SP-B; Akinbi et al., 1997).

Lungs of 6-8 week-old mice were inflation fixed (Bunkingham and Weyder, 1981) with ice cold 2% paraformaldehye and 2% glutaraldehyde in 0.1 M sodium cacodylate buffer (SCB), pH 7.3, postfixed in fresh fixative at 4 °C overnight, incubated with 1% osmium tetroxide in 0.1 M SCB at room temperature for 2 hours, and stained en bloc with 4% aqueous UA overnight.

Increasingly, cells isolated from blood and body fluids and cells grown in culture are becoming the experimental models of choice for biological research. The demand for demonstrating biochemical processes morphologically is also becoming commonplace in the electron microscopy laboratory. Successful fixation, in situ embedment, and ultrathinsectioning of cell monolayers can be difficult to achieve for routine transmission electron microscopy. For postembedding immunocytochemistry, processing becomes more complex due to fixation constraints and the use of acrylic resins. The object of this paper is to present a reliable, rapid method for processing monolayers that preserves both the ultrastructure of the cells and antigenicity.

The equipment used for this procedure was a Pelco Model 3440 MAX laboratory microwave oven equipped with a temperature probe and a maximum power output of 800 watts. Using a neon bulb array, the oven cavity is calibrated to determine the microwave energy distribution.

The focused ion beam (FIB) has become an indispensable tool for a variety of applications in materials science, including that of specimen preparation for the transmission electron microscope (TEM). Several FIB specimen preparation techniques have been developed, but some problems result when FIB specimens are analyzed in the TEM. One of these is X-ray fluorescence from bulk material surrounding the thin membrane in FIB-prepared samples. This paper reports on a new FIB specimen preparation method which was devised for the reduction of X-ray fluorescence during energy dispersive X-ray spectroscopy (EDS) in the TEM.

Figure 1 shows three membrane geometries that were investigated in this study on a single-crystal Si substrate with a RF sputter-deposited 50 nm Ni film. Membrane 1 is the most commonly reported geometry in the literature, with an approximately 20 urn wide trench and a membrane having a single wedge with a 1.5° incline.

The focused ion beam (FIB) lift-out method is a high precision technique by which site-specific cross-section transmission electron microscopy (TEM) specimens may be rapidly prepared from virtually any material. The technique is particularly useful when the sample geometry or composition is complex (e.g., fibers, powders, composites and interfaces). In addition to the preparation of TEM specimens, FIB milling has also found widespread utility in micromachining and microfabrication applications as well as specimen preparation for scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS).

As the applications of the FEB instrument continue to become more universally recognized, the need to understand the interrelationships between the target material, processing parameters, and process efficiency of the milling phenomena becomes more critical. Incident ion attack angle, target material stopping efficiency and sputtering yield, Y, are important variables governing the milling process. TRIM, a binary collision approximation Monte Carlo simulation code, is used to physically model variables that influence FIB sputtering behavior.

The results of TEM analyses of materials are critically dependent on the quality of the sample prepared. Although numerous techniques have been developed in the last two decades, differential thinning of inhomogeneous materials remains a serious problem. Recently, focused ion beam (FIB) technique has been introduced for cross-sectional sample preparation for TEM and SEM.

A novel system for depositing a fine-grain (∼ 200 nm) ceramic coating on a metal surface via a patent pending Small-Particle Plasma Spray (SPPS) technique has been developed at the Basic Industry Research Laboratory of Northwestern University. To understand the properties of the coated surface, the ceramic/metal interface and the microstructure of the ceramic coating must be investigated. This paper presents a comparison of the microstructure of an A12O3 coating on a mild steel substrate prepared using conventional and FEB techniques.

Sample preparation for transmission electron microscopy (TEM) has been a source of speculation with regards to potential for the creation of artifacts which may confound data gleaned from TEM analysis. For semiconductor integrated circuit (IC) materials characterization, the most common sample preparatory methods are based on final thinning by ion beam milling. The latest shift towards Copper / low dielectric constant (k) composite systems in the semiconductor IC industry provides several challenges for TEM sample preparation resulting from differences in milling rates and materials properties for neighboring features.

In conjunction with process development for integration of Cu / low-k materials, conducted at SEMATECH, we have systematically studied the effects of TEM sample preparation by ion milling in order to search for artifacts that could result from sample thinning procedures. For this purpose we have studied wafers with patterned copper lines isolated by a low-k polymer. One sample was stressed by thermal and electronic bias, while a second was subjected to only thermal stress.

The cross-sectioning of semiconductor wafers for SEM studies has traditionally been carried out by tedious and laborious mechanical grinding and polishing techniques. The mechanically polished surfaces are treated using a “wet chemical” etching method to enhance and delineate certain features or layers in a given specimen. The etched specimens are then coated by conductive layers to prevent charging during SEM examination. As an alternative to “wet chemical etching”, broad-ion beam etching techniques have been developed for surface treatment of mechanically polished specimens. More specifically, we have reported [1] the utilization of a combined process of broad-ion beam etching and coating of mechanically cross sectioned semiconductors in a single vacuum chamber. As a further progress to that work, we report a rapid and reliable technique for preparing precision SEM cross sections. The technique is based on perpendicular broad-ion beam milling of cleaved wafers to expose any desired cross-section through a given feature of the specimen.

The Small Angle Cleavage Technique (SACT) is a relatively simple and inexpensive method of producing superior cross sectional TEM specimens. For speed of preparation, it is unsurpassed; for example, ten samples can easily be prepared in about an hour from a typical material. It is particularly well suited for rapidly examining coatings and thin films very soon after they have been deposited. A major limitation of the technique is that it does require the substrate material to cleave or fracture. For this reason, it has been applied almost exclusively to semiconductor materials, but the technique has been extended quite successfully to other substrates such as glass, silicon carbide, quartz, sapphire, and other hard materials. Several procedures have been added or modified to the original technique developed by McCaffrey that makes it much easier to get started in using the technique. A detailed pictorial outline of the technique has been described elsewhere by the authors.

The low voltage phosphors should be efficiently excited with an electron beam value lower than 500V. Thus the properties of low voltage phosphors are directly affected by the surface states of phosphors. Recently, to improve the properties of these phosphors, much analysis has been carried out focused on the surfaces of phosphors using by FESEM, AES or XPS etc.. Nevertheless, the microstructure of phosphors around the surface has not been made clear due to the resolution limits of the above equipments and the difficulties of sample preparation. In this study, in order to analyze the microstructure of phosphors around the surface, we have prepared the thin sections of the (ZnxCdy)S phosphors by an ultramicrotome and carried out high resolution electron microscope(HREM) study on the thin sections.

To carry out ultramicrotomy, the particles of phophors were embedded with acrylic resin (methyl methacrylate: n-butyl methacrylate= 4:6, Benzoyl peroxide 1.5%) in a capsule.

Further development of Vacuum Fluorescent Displays (Fig.l) for low cost production and high yield requires investigation of all the components on a submicron scale at various processing stages.

A variety of specimen preparation methods have been used for making different types of high quality cross-sectional and plan-view TEM specimens from:

1. 1. Initial phosphor materials - ZnCdS powders admixed with conducting powder of ln2O3;

2. 2. In2O3 mixed ZnCdS phosphor layers of ready-made working VFD;

3. 3. W - filament cathodes coated with (Ba,Sr,Ca) oxides.

4. Rapid sharing of results.

Group 1 specimens were made both by direct dispersion of phosphor powder particles on the carbon coated copper grid from acetone diluted powder suspension, and by preparation of cured bulk material from the powder using Gatan G-l epoxy, followed by cutting, grinding-dimpling and final ion milling in Gatan DuoMill 600 (Fig.2).