Ultramicrotome sectioning

Nitrogen adsorption isotherms were measured with a sorbtometer Micromeretics Asap 2010 after water desorption at 130°C. The distribution of pore radius was obtained from the adsorption isotherms by the density functional theory. Electron microscopy study was carried out with a scanning electron microscope (SEM) HitachiS800, to image the texture of the fibers and with a transmission electron microscope (TEM) JEOL 2010 to detect and measure metal particle size. The distribution of particles inside the carbon fibers was determined from TEM views taken through ultramicrotome sections across the carbon fiber. 

Fig. 9. A transmitted electron micrograph of an ultramicrotomed section of an aluminum-epoxy interphase. The highly ordered structure in the center is a 3.3 micron thick aluminum oxide layer present on the base metal. The featureless area is the epoxy matrix. The light areas within the oxide are fractures caused by the microtoming. The epoxy has however penetrated to the bottom of all of the 50 nm pores in the oxide...

Measurements. The morphology of the blends was studied by optical microscopy (Leitz Dialux Pol), transmission electron microscopy (Jeol 100 U), and scanning electron microscopy (Cambridge MK II). Ultramicrotome sections were made with an LKB Ultratome III. Samples for scanning electron microscopy were obtained by fracturing sheets at low temperature. The fracture surfaces were etched with a 30% potassium hydroxide solution to hydrolyse the polycarbonate phase. Stress-relaxation and tensile stress-strain experiments were performed with an Instron testing machine equipped with a thermostatic chamber. Relaxation measurements were carried out in flexion (E > 108 dyn/cm2) or in traction (E < 108 dyn/cm2). Prior to each experiment, the samples were annealed to obtain volumetric equilibrium. 

Figures la, lb, lc, and Id show transmission electron micrographs of the blends with 5, 10, 20, and 25 wt% PST, respectively. PC forms the continuous phase and PST is dispersed as spherical particles without any aggregation. The observed oval shape of the dispersed particles results from the deformation of the specimens during ultramicrotome sectioning. Their normal spherical shape is evident from scanning electron micrographs of the etched fracture surface of these blends (Figure le).

The authors are indebted to N. Overbergh for electron microscope investigations, A. Van Dormael for the preparation of the ultramicrotome sections and R. De Wil for the photographic work. They are also indebted to the Ministry of Scientific Programming and to the National Fonds voor Wetenschappelijk Onderzoek (N.F.W.O.) for equipment and financial support. We also wish to thank the Belgian Ministry of National Education for a fellowship (S.C.) and to thank the Ministry of Education of India. 

Figure 3.16. STEM image performed in SEM on cryo-ultramicrotomed sections of P(S-ABu)/MWCNT nanocomposites films in annular dark-field conditions at 30 kV the contrast between the fillers and the matrix is important. Scale bar 500 nm.

Fig. 3b. Graft copolymer microstructure (transmission electron micrograph, ultramicrotome section) after processing to a milled sheet...

Fig, 4a. Pressed sheets consisting of PMMA and of PMMA grafted elastic siloxane particles (powder from Fig. 3a transmission electron micrographs, ultramicrotome sections) 10 wt. % core/shell particles... 

Figure 2. (a) TEM images of an ultramicrotomed section of the anodic alumina films formed in 0.3 M phosphoric acid at 60 V (b) SEM images of anodic films fomied in 0.3 M phosphwic acid at 140 V and (c) in 1 vol% phosphoric acid at 178 V. Arrows in (a) show individual defeds. 

In the transmission electron microscopic (TEM) studies, we found that it was exceedingly difficult to obtain ultramicrotomed sections of iPS-iPP blends, whereas the iPS-fo-iPP diblock copolymer could be cut with relative ease. This result exhibits one major difference between the diblock copolymer and the corresponding homopolymer blend. Unfortunately, owing to the difficulty of finding a selective staining technique, the sample of diblock copolymer did not display visible contrast or obvious structural features in the TEM studies. However, the results of SEM studies do reveal a clear difference between the blend and the diblock copolymer the macrophase separation is revealed on the etched surface of the blend and is not present in the copolymer (Figure 3). The diblock copolymer exhibits only a finely dispersed and continuous submicron structure throughout the field of view, as expected. 

Figure 2. SEM (a,b) and TEM (c) micrographs of the structure xerogel/anodic alumina (a) - as anodized anodic alumina film of 5 pm thick fabricated on Si, (b) - after one spin-on deposition of Eu-doped titania xerogel (c) - ultramicrotomed sections of the terbium-doped alumina xerogel/PAA structure of 30 pm thick. Bottom of the pore was filled with terbium-doped alumina xerogel after five spin-on depositions.

Figure 2. Transmission electron images of ultramicrotomed section of the alloy coated with sol-gel with incorporated nanoparticles (a) at the coating/substrate interface (b) high-resolution image of the coating showing individual nanoparticles.

Fig. 2.20 TEM image along with the particle size distribution of an ultramicrotomed section of a planar Ag nanoparticle smectic hybrid film as shown in Fig. 2.18. Adapted with the permission from Ref [78]. Cop5uight 2013 American Chemical Society...

Figure 6.8. The art of sectioning, (a) Schematic explanation of the two-step sectioning method to be used for soft materials. (b) Schematic cross-sectional view of an ultramicrotomed section.

Figure 1.61 Comparison of visibility of lamellae in PE sections with thicknesses of 0.2 pm (top), revealing single lamellae inside a banded spherulite, and 2 pm (bottom) with superposition of irregularly arranged lamellae (stained, ultramicrotome sections, 1000 kV HEM)...

FIGURE 10. TEM analysis of a ultramicrotomed section through the peeling face of a joint of 2024-T3 A1 clad bonded with adhesive A good wetting of the aluminum and some failure through the oxide layer can be seen. Reprinted with permission from Reference 17. Copyright 1984 Butterworth Scientific Ltd. 

Generally, microtomy refers to the preparation of thin slices of material by sectioning for observation in an optical microscope by transmitted light. Microtomed sections are cut with steel or glass knives to about 1 to 40/tm thickness. Ultramicrotomy methods involve the preparation of ultrathin sections of material for observation in an electron microscope. Ultramicrotome sections are cut with glass or diamond knives to a thickness ca. 30-100 nm. If imaging is to be done via many techniques, the TEM preparation method can be utilized to prepare thin sections for OM, TEM, and AFM, and the flat block face is used for SEM and/or SPM. 

Figure 7 shows an electron micrograph of an ultramicrotomed section of a polystyrene-h/ock-polybutadiene-h/oc/c-polystyrene copolymer in which the domain morphology consists of polystyrene cylinders in a polybutadiene matrix. The specimen was sectioned from a compression-moulded sheet. 

Fig. 2. TEM micrograph of an ultramicrotome section of zeolite Pt-mordenite (from [7])...

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