Small-angle neutron scattering crystals

Hamley I W, Garnett S, Luckhurst G R, Roskilly S J, Pedersen J S, Richardson R M and Seddon J M 1996 Orientational ordering in the nematic phase of a thermotropic liquid crystal A small angle neutron scattering study J. Chem. Phys. 104 10 046-54... 

L.E. Iton, F. Trouw, T.O. Brun, J.E. Epperson, J.W. White, and S J. Henderson, Small-Angle Neutron-Scattering Studies of the Template-Mediated Crystallization of ZSM-5-Type Zeolite. Langmuir, 1992, 8. 1045-1048. 

In the latter two phases backbones have the spindle-like conformation, i.e., the prolate shape with (R%) > R p), the characteristic of main chain liquid crystalline polymers. Important means of investigating the conformations of side chain liquid crystalline polymers include small angle neutron scattering from deuterium-labeled chains (Kirst Ohm, 1985), or small angle X-ray scattering on side chain liquid crystalline polymers in a small molecular mass liquid crystal solvent (Mattossi et al., 1986), deuterium nuclear resonance (Boeffel et al., 1986), the stress- or electro-optical measurements on crosslinked side chain liquid crystalline polymers (Mitchell et al., 1992), etc. Actually, the nematic (or smectic modifications) phases of the side chain liquid crystalline polymers have been substantially observed by experiments. 

This finding is quite important in the study of chain-folding mode in the lamella. The D and H chain stems are statistically randomly distributed in the lamella as clarified by the quantitative interpretation of the infrared band profile. The thermal data and the wide-angle and small-angle neutron scattering data also support this concept. Lrom all these data, we concluded that the PE chains show almost perfectly random reentry mode when crystallized from the melt, as far as a pair of DHDPE and LLDPE(2) is concerned. 

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