Polarization optical microscopy

To detect experimentally produced shock effects in small recovered specimens, techniques with high spatial resolution are required. We used a combination of optical (polarizing microscopy) and electron-optical (scanning and transmission electron microscopy) techniques, enabling characterization from the scale of the recovered bulk sample down to the atomic level. Because recent advancement in... 

To investigate whether, or not, cocrystallization occurs, in the P(3HB-co-3HP) copolymer, the solid-state structure was analyzed by high resolution NMR, X-ray diffraction, DSC and optical polarizing microscopy, for a series of P(3HB-co-3HP) samples with the 3HP content ranging from 0 mol% (bacterially synthesized 3HB homopolymer) to 100mol% (chemically synthesized 3HP homopolymer, i.e., polypropiolactone, PPL) [67]. 

The pleated sheet can also be observed with optical polarization microscopy [119, 133]. Fig. 15 demonstrates the origin of the various banded patterns in the polarizing microscope, which are seen on a longitudinal section of a fiber. In the dark areas the chains are aligned parallel to the analyzer or polarizer direction. Such a banded texture is often observed in films and fibers of lyotropic and thermotropic polymers. 

DSC curve. The optical polarizing microscopy study of this sample indeed shows multiple transitions in the anisotropic phase. 

The optical polarizing microscopy analysis of these copolymers showed in all cases schlieren nematic textures, in contrast to the corresponding polyethers which present smectic type textures. All these copolyethers are soluble in aromatic and halogenated solvents. 

Percec and coworkers [184] utilized a similar strategy for the conversion of perfluorinated alkylene functionalized 3,4,5-trihydroxy benzoic acid-type dendrons into methyl methacrylate functionalized dendritic macromonomers. Characterization of the resulting linear-dendritic architectural copolymers involved DSC, x-ray diffraction, and thermal optical polarized microscopy. It was concluded that the self-assembly of the pendant dendritic mesogens forced the linear backbone into a tilted, helical ribbon-type structure. The self-assembly behavior was largely controlled by the multiplicity, composition, and molecular weights of the pendant dendritic mesogens. 

Samples prepared in this way were studied by x-ray diffraction, infrared absorption and optical polarizing microscopy and errors in the accuracy of the results were always present because of the large pressure gradient. In this ungasketed configuration, sample pressures not much greater than 30 GPa were reached before cracks developed in the diamond anvils ultimately leading to failure. 

Figure 7. Schematic diagram of the optical features of the ruby fluorescence pressure measuring and optical polarizing microscopy systems.

An illustration of optical polarizing microscopy is provided by Fig. 9 which shows a photograph of a sample of powdered RDX compacted in a gasketed DAC at 2.0 GPa and room temperature in a Pt-Rh gasket. 

The a-7 phase boundary of RDX was also determined by optical polarizing microscopy of single crystals of RDX in a quasihydrostatic environment. Fig. 12 shows two single crystals of RDX at about 3.5 GPa at room temperature in a Fluoroinert (chemically inert fluorinated hydrocarbon) pressure transmitting medium which provides a hydrostatic environment up to about 4.0 GPa at room temperature. At constant pressure, as the temperature is increased the hydrostatic limit increases because temperature reduces the viscosity of the liquid. This... 

As noted above, a combination of high pressure diamond anvil techniques, all utilizing the ruby fluorescence method of pressure measurement, were used to carry out these experiments. These include (1) Fourier transform infrared (FTIR) spectroscopy for the kinetic measurements [9-11], (2) energy dispersive x-ray powder diffraction for crystallographic identification of the observed polymorphic forms and also compression measurements [12], (3) optical polarizing microscopy... 

The apparent absence of LC transition temperatures and glass-transition temperatures in the hybrid copolymers with >10 mol % POSS indicated that the presence of POSS moieties in the hybrid copolymers made it more difficult to orient or order LC mesogens as the amount of the POSS component increased. Orientation became more difficult because the rigidity and bulkiness of POSS lowered the mobility and flexibility of the hybrid copolymer. Differential scanning calorimetry (DSC) and optical polarizing microscopy showed the 10% POSS copolymer had a smectic mesophase-like fine-grained texture. Moreover, the 10% POSS LC copolymer had better thermal stability than that of the corresponding LC homopolymer. 

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