Geometry chain

Since the value of (r ) is a property of the polymer only, depending as it does only on chain geometry, it follows that the condition of the polymer at the 6 temperature in different solvents is exactly the same. The polymer behaves as though it were thermodynamically ideal showing no interaction at all with the solvent. 

The SANS experiment is applicable to polymeric networks containing some deuterium labeled chains. The chain geometry can be probed not only in the unperturbed network, but changes in chain shape and size can be measured as a function of strain or swelling. This enhances the applicability of SANS experiments for elastomeric systems. 

M. Grell, D.D.C. Bradley, X. Long, T. Chamberlain, M. Inbasekaran, E.P. Woo, and M. Soliman, Chain geometry, solution aggregation and enhanced dichroism in the liquid-crystalline conjugated polymer poly(9,9-dioctylfluorene), Acta Polym., 49 439-444, 1998. 

Derivatives of Linear Chain Geometry. The molecular structure... 

In an early attempt to model the dynamics of the chromatin fiber, Ehrlich and Langowski [96] assumed a chain geometry similar to the one used later by Katritch et al. [89] nucleosomes were approximated as spherical beads and the linker DNA as a segmented flexible polymer with Debye-Huckel electrostatics. The interaction between nucleosomes was a steep repulsive Lennard-Jones type potential attractive interactions were not included. 

The crystal structure of the N-terminal 80 residues of tropomyosin (Brown et al., 2001) contains its first alanine cluster and displays two specific consequences of this motif for the main-chain geometry of the coiled-coil. One is that the coiled-coil in this segment becomes locally narrow, to 8.0 A diameter, as would be expected from alanine s small size. This feature is directly related to the stability of the coiled-coil in a 10 A wide dimeric coiled-coil, a pair of core alanines from the opposite helices would generally leave unfilled spaces in the interior these spaces become smaller as the main chains of the helices approach each other and the core becomes more close-packed. Recent studies of model coiled-coils with identical amino acid compositions, but different arrangements,... 

In an investigation of the effect of chain geometry on the two phase morphology of polystyrene-polyisoprene block copolymers, Price et al. have studied films of AB linear, AB stars with 2,3 or 4 branches196,197), graft copolymers 198 200>, and ABC block terpolymers201. ... 

Fig. 3. Single chain geometry of a segment of the organometallic PPE derivative 65a. Planarization of the backbone in these materials is not favorable due to the added-on cyclopentadienylcobalt fragments that bulk up the main chain.

Unsubstituted CP crystals all have quite similar chain packings. The crystal sizes are always small (ca. 100 A in all directions) and imperfectly ordered usually, chains are longer than the crystal dimensions. Therefore, the ideal CP is not found in practice chain geometries fluctuate along their length, as well the interchain interactions. This disorder is to be taken seriously in physical study, not as a small perturbation. 

Fig. 7 Chain geometry of an azo-polysUoxane based on p - structural unit type (See also Plate 13 in the Colour Plate Section)...

These contributions to chain geometry and order confer both a much higher melting point to the resin and much higher tensile strength to spun fiber than is possible with the aliphatic nylons. 

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