Microtomed slice

The depth distribution of light stabilisers in coatings has been studied in 1 - 3 mg microtomed slices, by means of SFE-GC with ToF-SIMS and nitrogen thermionic detection, as well as by direct ToF-SIMS analysis results were in good agreement [59]. As the SFE effluent... 

When a colour layer of an artwork is analysed, a drop (5 10 pi) of this solution is localised on the sample surface. This method of enzymatic digestion can be, in principle, applied to all types of samples that occur in restoration practice fragments, cross-sections, microtome slices, etc. The samples are digested in closed microtubes to prevent evaporation of the solution. In the case of the cross-sections and microtome slices, it is essential to ensure the wetness of sample surface for the whole time of digestion. 

In polymers crystallized from the melt, in most cases spherulitic structures are observed spherical agglomerates of crystals and amorphous regions, grown from a primary nucleus via successive secondary nucleation (Figure 4.18). The dimensions of the spherulites are commonly between 5 pm and 1 mm. When spherulites grow during the crystallization process, they touch each other and are separated by planes. In a microtome slice they show a very attractive coloured appearance in polarized light. 

Fig. 24 A microtomed slice of a catalyzed Nafion 117 membrane used in a DMFC, imaged with an electron microscope. Two features gleaned from this image have been the sharpness of the catalyst layer/membrane interface (on the scale of the image shown) and a measured thickness of the catalyst layers about twice that calculated from perfect space filling by the composite catalyst layer material. The latter suggests a high fraction of free volume, facilitating gas transport [52].

A TEM image of a fOO-nm thick cross-section of a TEM membrane prepared by microtome slicing is shown in Fig. 4.25 [125]. The membrane thickness... 

Fig. 4.25. TEM image of a 100-nm thick sliver of a TEM window cross-section prepared by microtome slicing supported on a glassy carbon grid (on the right side of the image). The thicknesses of the Si3N4 (30 nm), Si02 (7 nm), and the interfacial layer between the Si and Si3N4 are shown (from [125])...

The surface modification was further followed by FTIR (ATR) spectroscopy on a Perkin-Elmer System 2000. Analysis was performed with an internal reflection element (GaAs crystal, 45° incidence angle) with 100 scans co-addition and a resolution of 4 cm . The insoluble, inert PTFE was cut into thin microtome slices between 150-500 nm and analyzed in transmission mode. 

Figure 5.18 Section of a HR-TEM image of a microtome slice of a crystal of thermally treated [CU7oSe35(PEt2Ph)23] (4)-...

Bonded Samples, Microtome Slices and Photographs for the Evaluation of the Penetration... 

Optical measurements provide valuable information about alignment kinetics, and electron microscopy of aligned samples provides clues about the alignment process. Microtomed slices were taken fi om PS-PMMA block copolymer materials that were aligned in an electric field (far from the edges of the samples) [65]. Alignment was verified by SAXS. Some slice planes were parallel to the electrodes (parallel slices) and others perpendicular to the electrodes (perpendicular slices), as shown in Fig. 27. The slices were stained with ruthenium tetroxide and viewed with a transmission electron microscope. Several classes of defect structures were observed +1/2 disclination lines and defect walls were most prevalent, and... 

FIGURE 28 Transmission electron micrographs of microtome slices of an aligned PS-PMMA block copolymer sample. In (a), the slice plane was perpendicular to the electric field direction, and in (b) and (c) the slice plane contained the electric field direction. Intersection of the slice plane with +1/2 and -1/2 disclination lines and wall defects (denoted with a w ) are indicated in (a). (Reprinted with permission from Ref. 65.)... 

Concentration profiles were measured using microtomed slices and FTIR microspectroscopy.Similar methods are used for determination of other additives in polymers (e.g., UV stabilizers in polymer degradation studies). Further studies using this method should provide data, which confirm that slicing conditions (especially temperature) do not introduce error. This method, if developed to its full capabilities, has full potential to produce data not affected by conditions of measurement. 

To increase the quality of images, it is recommended that the nanocomposite be extruded or compression molded into a film in order to orient the clay plates. The film is then mounted in the epoxy such that the microtome slices are cut normal to the surface of the films. This will ensure that the maximum number of plates will be edge on in the TEM image. In a typical X-ray diffraction experiment, the sample can be prepared and run in an hour or two. 

Wang, X., Zhou, W. Glass transition of microtome-sliced thin films. Macromolecules 35 (18), 6747-6750 (2002)... 

For thermosetting resins, the effect of nanoconfinement on the glass transition temperature of thin films has only been examined by one research group [8]. In that work, the glass transition temperature of the microtome-sliced epoxy thin film is found to decrease with film thickness, and the Tg is depressed by 7.8°C for a 40 mu thin film [8]. On the other hand, no studies have examined the effect of curing thermosetting resins under nanoscale constraint, although considerable efforts have... 

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