Contrast Modes

Chemical Shift, 13 Relevant Techniques, 13 Recent Development Multidimensional NMR, 14 

4 Small-Angle Neutron Scattering, 21 Differential Scanning Calorimetry, 22 

In this chapter, the principle, recent developments, and selected applications of some commonly used experimental techniques for characterizing semicrystalline polymers are described.These techniques include optical microscopy, electron microscopy (transmission and scanning), atomic force microscopy, nuclear magnetic resonance, diffraction and scattering (X-ray, neutron, and 

Handbook of Polymer Crystallization,Vast Edition. Edited by Ewa Piorkowska and Gregory C. Rutledge. 2013 John Wiley Sons, Inc. Published 2013 by John Wiley Sons, Inc. 

The common contrast modes include polarized light, phase contrast, differential interference contrast, and Hoffman modulation contrast [5]. Depending on the nature of the polymer, such as refraction index, sample thickness, and optical anisotropies in the materials, different modes of transmission optical microscopy can be employed by mounting special accessories in a classic optical microscope to overcome different problems. For example, a polarizer and analyzer can be mounted before and after the sample to construct a polarized light microscope, commonly used for semicrystalline polymers a phase plate and phase ring can be added to construct a phase contrast optical microscopy, which is common for studying a noncrystafline multiphase polymer system. 

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Shi P, Zhang J. Contrasting modes of evolution between vertebrate sweet/umami receptor genes and bitter receptor genes. Mol. Biol. Evol. 2006 23 292-300. 

Figure 1.33 Comparison of light transmission images of glass fiber-reinforced polyamide in (a) bright-field and (b) phase contrast modes. (Reproduced with kind permission of Springer Science and Business Media from L.C. Swayer, and D.T. Grubb, Polymer Microscopy, Chapman Hall, London. 1996 Springer Science.)...

A contrasting mode of flavoprotein reactivity with an acetylenic inactivator occurs in the reaction of 2-hydroxy-3-butynoate (13, Fig. 15) with a number of a-hydroxy acid oxidizing enzymes. This process is exemplified by the inactivation of L-lactate oxidase from Mycobacterium smegmatis, an enzyme which catalyzes the oxidative decarboxylation of lactate to yield acetate, carbon dioxide, and water (Walsh, 1979, p. 408). Incubation of 13 with lactate oxidase leads to inactivation of the enzyme with a partition ratio that varies from 110 in the... 

Optical microscopy on phase contrast mode allows observation of the different morphologies obtained for each PP/interfacial modifier/PA6 blend. By image analysis techniques, it is possible to carry out statistical field measurements not only of the mean number of particles on the dispersed phase but also of their preferential geometry, mean size, and size distribution. 

A) Bright-Held diffraction contrast mode B) Dark-field diffraction contrast mode C) High-resolution imaging mode a) Specimen b) Lens c) Aperture d) Screen... 

Atomic force microscopy (AFM) images in phase-contrast mode of PS-COOH/polymethyl methacrylate (PMMA)-NH2 = 40/60 (vol.%) prepared at 190°C (A) (B) like (A), prepared at 200°C (C) like (B), with SCA (D) like (B), with SCA+Pt (frame size 10 x 10 pm). Influence of silane-containing coupling agent (SCA) and processing conditions on morphology of PS-COOH/PMMA-NH2 = 40/60 (vol.%) blends. (From J. Pionteck, V. B. Sadhu, L. Jakisch, P. Potschke, L. HSufiler, and A. Janke, Polymer 46,6563-6574, 2005. With permission.)... 

The recommended procedure for examining samples for cork dust is to use a stain that reacts with lignin, a structural macromolecule in cork. When it is necessary to evaluate color development, the microscope should be operated in brightfield rather than phase-contrast mode. 

Peterson RB, and Havir EA. Contrasting modes of regulation of PSll light utilization with changing irradiance in normal and PsbS mutant leaves of Arabidopsis thaliana. Photosynth Res. 2003 75 57-70. 

The vesicles were observed on an inverted microscope in phase-contrast and confocal fluorescence modes, as follows. The white cloud of lipid was gently dispersed in the tube and introduced into an observation chamber. The chamber was filled with the same solution as the internal solution except that 0.1 M sucrose was replaced with 0.1 M glucose (external solution). Because of the difference in the reffactivity of the internal and external solutions, the contrast of the vesicle s images was enhanced in the phase-contrast mode. For the confocal fluorescence microscopy, a confocal scanner unit (CSU 10, Yokogawa, Japan) was used, and the lipophilic fluorescent dye Nile Red (Molecular Probes, Inc., OR, USA) was added to the starting lipid solution at 0.3 wt% of the lipid. 

Large sampling depth (few nm to few /rm depending on accelerating voltage and high-contrast mode of analysis)... 

The contrasting modes of failure were photographed for Figure 21. Adhesive retention by the fabric caused the glossy blackness of the right hand sample. Prop. Add. is an abbreviation for proprietary additive and refers to the crossbridging agent. 

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