Electron diffraction poly

Figure 3. Electron diffraction of poly(TCDU) formed under conditions specified in...

Figure 4. Electron diffraction of poly (DM DA) from Figure 2.

Liu et al. prepared palladium nanoparticles in water-dispersible poly(acrylic acid) (PAA)-lined channels of diblock copolymer microspheres [47]. The diblock microspheres (mean diameter 0.5 pm) were prepared using an oil-in-water emulsion process. The diblock used was poly(t-butylacrylate)-Wock-poly(2-cinna-moyloxyethyl) methacrylate (PtBA-b-PCEMA). Synthesis of the nanoparticles inside the PAA-lined channels of the microspheres was achieved using hydrazine for the reduction of PdCl2, and the nanoparticle formation was confirmed from TEM analysis and electron diffraction study (Fig. 9.1). The Pd-loaded microspheres catalyzed the hydrogenation of methylacrylate to methyl-propionate. The catalytic reactions were carried out in methanol as solvent under dihydro-... 

Few neutron or electron diffraction studies have been reported, although the neutron structure analysis of substituted poly(benzobisthiazole) and poly(benzobisoxazole) derivatives of 19 and 5 has been reported and the torsion angle between the benzobisthiazole and phenyl rings was shown to be 7.2° larger than that determined from X-ray methods <1999MM4010, 2001MM2012>. 

The arrangement of helices in the solid and liquid crystalline states of poly(a-phenylethyl isocyanide) were determined by X-ray and electron diffraction. Well-defined diffraction patterns were obtained from oriented films using selected area electron diffraction. Intermolecular and intramolecular patterns were calculated from the five Debye-Scherrer rings. All the reflections were indexed in terms of a pseudo-hexagonal triclinic unit cell, with... 

Electron microscopy revealed that the morphology of 6% Cl doped PITN depends on the substrate on which it is deposited and that it is a relatively "open" structure, although not as open as poly(acetylene). Selected area electron diffraction on the same sample showed the material to be partially crystalline (three diffraction rings could be seen). 

Polymers of type shown on in Figure 4.28(b) were also investigated. For materials with five PV units, well-defined nanostructures were observed which are spaced 8 nm from center to center and have a length of 80 nm. Electron diffraction measurements show that the rods are packed into the same structure as the poly(p-phenylene vinylene) homopolymer. The rods are again perpendicular to the surface. When only two PV units are present, no nano-scale organization is observed and glassy solids were obtained instead. This latter observation shows that in order to obtain ordered nanostructures, a rod containing two PV units is not sufficient. 

AFM Atomic force microscopy BFDC Bright-field diffraction contrast DFDC Dark-field diffraction contrast ED Electron diffraction PTFE Poly(tetrafluoroethylene)... 

Structure of the Collapsed Monolayers. IR spectra of specimens prepared from air dried collapsed monolayers were typical of specimens in the a-helical conformation with no indication of any p conformation. Electron diffraction patterns gave a similar result. The patterns for poly-(L-leucine) and poly(L-norleucine) are similar to poly(L-norvaline) (12) with low crystallinity. A strong equatorial reflection at 10.94 0.10 A is observed in poly(L-leucine). If we assume as previously (5) that this is the 100 reflection from a hexagonal cell, the calculated area per residue in the monolayer is 17.3 A, assuming the molecular separation is the same as in the collapsed film. This figure is in agreement with the observed area of 16 A in view of the difficulties encountered in spreading the monolayer. 

Figure 4. Electron diffraction patterns from collapsed monolayers, (a) Poly(i.-methionine). The outermost reflection at 1.49 A is not visible on this photograph the sharp meridional reflection is 006. (b) 1 1 poly(i.-alanine) + poly(i>-...

From the electron diffraction observations the calculated area per residue in a monolayer of poly(L-methionine) is 17.2 A the area observed is 16.5 0.5 A2. 

Electron diffraction patterns have been obtained from collapsed monolayers of poly (alanine) and poly (y-benzyl glutamate). The enantiomorphic forms of the other two polymers give patterns with very poor crystallinity, and their racemic mixtures have not therefore yet been investigated. The principal features of the diffraction pattern of poly-... 

The structure and spectra of /3-poly(L-glutamic acid) [ -(GluH) ] and its salts have been studied in some detail. X-Ray and electron-diffraction studies (Keith et al., 1969a,b), particularly on the Ca salt [)3-(GluCa) ], have indicated that this polypeptide forms an APPS structure. A model has been presented for the structure, and coordinates have been given for the atoms in the unit cell (Keith et al., 1969a), but a detailed test was not possible because of the paucity of diffraction data. 

Electron diffraction from poly (TCDU) is shown in Figure 7, and corresponds to the pol3oner phase 2, shown in Table III. This phase is not usually observed in bulk crystals pol)niierized under routine conditions >... 

---