Poly alignment

For aprotic polar organic solvents only few widely applicable alignment media are known. The lyotropic mesophase of poly(y-benzyl-L-glutamate) (PBLG) with DMF [37] has the disadvantage of a relatively strong minimum alignment. Bicellar... 

K., Heckmann, D., Paululat, T., Kessler, H., Luy, B. Stretched poly(vinyl actetate) gels as NMR alignment media for the measurement of residual dipolar couplings in polar organic solvents. Angew. Chem. Int. Ed. 2005, 44,... 

Freudenberger,. C Spiteller, P., Bauer, R Kessler, H Luy, B. Stretched poly(dimethylsiloxane) gels as NMR alignment media for apolar and weakly polar organic solvents an ideal tool for measuring RDCs at low molecular concentrations. /. Am. Chem. Soc. 2004, 326, 14690-14691. 

We now report that in the region of the absorption band the flow linear dichroism of a solution of 1 is positive (Fig. 3). Assuming that the nature of the flow orientation is of the usual kind, i.e., that the polymer chains in a random coil conformation which dominates in solution (34) tend to align with the flow direction, this observation provides additional support for the absolute assignment of the transition moment direction along the chain direction, even in solution. Similar conclusions based on polarization studies on a stretched film of poly(di-n-hexyl silane) have recently been reported (36). 

We can divide commodity plastics into two classes excellent and moderate insulators. Polymers that have negligible polar character, typically those containing only carbon-carbon and carbon-hydrogen bonds, fall into the first class. This group includes polyethylene, polypropylene, and polystyrene. Polymers made from polar monomers are typically modest insulators, due to the interaction of their dipoles with electrical fields. We can further divide moderate insulators into those that have dipoles that involve backbone atoms, such as polyvinyl chloride and polyamides, and those with polar bonds remote from the backbone, such as poly(methyl methacrylate) and poly(vinyl acetate). Dipoles involving backbone atoms are less susceptible to alignment with an electrical field than those remote from the backbone. 

Fig. 3. Alignment of poly(HA) depolymerase catalytic active amino acids. Amino acids of the catalytic triad and the conserved histidine residue of the putative oxyanion are shown in bold letters. The positions (pos.) of respective amino acids of mature depolymerase proteins are indicated. Amino acids conserved in all poly(HASCL) depolymerases are indicated in capital letters, those which have been conserved in ten or more proteins are marked by low letters in the consensus sequence. indicates amino acids with hydrophobic side chains + indicates amino acids with a small side chain...

Recently, two new poly(3HB) depolymerase sequences from A. faecalis AE122 and from P. stutzeri were published which contain two instead of only one poly(3HB)-binding domain [57, 64]. Two types of poly(3HB) binding domains can be differentiated by amino acid alignment (types A and B in Fig. 4). Several amino acids are strictly conserved in both types of binding domains. It is not known whether these conserved amino acids are necessary to constitute a particular three-dimensional structure or whether these amino acids are directly involved in the interaction with the polymer chain. 

Fig. 4. Alignment of poly(HASCL) depolymerase C-terminal substrate binding domains. Two types of poly(HASCL) depolymerase C-terminal substrate binding domains (A and B) can be distinguished by amino acid alignment. Amino acids strictly conserved in all depolymerase proteins are indicated...

The pathway and kinetics of the C to S transition have been studied on shear-aligned cylinders of the commercial diblock copolymer of PS and poly(ethylene-co-butylene) (KRATON G 1657 Shell Chemical Company) [143, 144], A complete dissolution of the cylindrical structure before the epitaxial... 

Two diacetylenes have been epitaxially polymerized as thin films in contact with alkali halide substrates. These films in contact with alkali halide substrates. These films consisted of highly oriented single crystals aligned along both <110> directions of the substrate. The structures of both poly(TCDU) and poly(DMDA) were modified by this technique and, in all cases, highly crystalline near-perfect films were achieved. 

In this method, NWs can be aligned by passing a suspension of NWs through microfluidic channel structures, for example, formed between a poly(dimethylsiloxane) (PDMS) mold 49 and a flat substrate (Fig. 11.3a). Images of NWs assembled on substrate surfaces (Fig. 11.3b) within micro-fluidic flows demonstrate that virtually all NWs are aligned along the flow direction. This alignment readily extends over hundreds of micrometers, and... 

K.S. Whitehead, M. Grell, D.D.C. Bradley, M. Jandke, and P. Strohriegl, Highly polarized blue electroluminescence from homogeneously aligned films of poly(9,9-dioctylfluorene), Appl. Phys. Lett., 76 2946-2948, 2000. 

T. Yamamoto, T. Murauyama, Z.-H. Zhou, T. Ito, T. Fukuda, Y. Yoneda, F. Begum, T. Ikeda, S. Sasaki, H. Takezoe, A. Fukuda, and K. Kubota, -ir-Conjugated poly(pyridine-2,5-diyl), poly(2,2 -bipyridine-5,5 -diyl), and their alkyl derivatives. Preparation, linear structure, function as a ligand to form their transition metal complexes, catalytic reactions, //-type electrically conducting properties, optical properties, and alignment on substrates, J. Am. Chem. Soc., 116 4832-4845,... 

FIGURE 5.8 Electroluminescence from an LED based on ITO-rubbed PPV-aligned poly(9,9-dioctyl fluorene)/Ca recorded through a polarizer oriented parallel (triangles) and perpendicular (circles) to the orientation direction. (From Whitehead, K.S., Grell, M., Bradley, D.D.C., Jandke, M., and Strohriegl, P., Appl. Phys. Lett., 76, 2946, 2000. With permission.)... 

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