Macromolecular structure crystallinity

Short range order in liquid-like systems as well as long range order in crystalline domains are reflected in WAXS-patterns very dearly. Some examples of calculated X-ray patterns from PTFE (Phase I), a smectic LC-phase and even a PE melt, show that our model covers a wide range of macromolecular structures running the whole scale from crystalline systems over mesophases up to polymer melts. The range of intra- and intermolecular order can be estimated fairly well with the help of density correlation functions. 

Such maps are primarily used to refine a trial structure, to find a part of the structure that may not yet have been identified or located, to identify errors in a postulated structure, or to refine the positional and displacement parameters of a model structure. A difference map is very useful for analyses of the crystal structures of small molecules. It is also very useful in studies of the structures of crystalline macromolecules, since it can be used to find the location of substrate or inhibitor molecules that have been soaked into a crystal once the macromolecular structure is known. A formula like that in Equation 9.1.5 is then used. When a structure determination is complete, it is usual to compute a difference electron-density map to check that the map is flat, and approximately zero at all points. 

Side chain liquid crystalline and nonlinear optical polymers (e.g. 37 and 38), which are conventionally produced by multi-step processes, are also available very easily via active ester synthesis. A unique feature of the active ester method for this purpose is that a single activated polymer intermediate can be used for the synthesis of any number of macromolecular structures, all by a simple single-step reaction pathway. Synthesis of such polymers by copolymerization of the... 

Samulski ET (1985) Macromolecular structure and liquid crystallinity. Farad. Discuss. Chem. Soc. 79 7... 

C-NMR spectroscopy and electron diffraction suggests that these consist of both triclinic (I-a) and monoclinic (I-/1) crystalline forms [33-36], Contrary to lignin, the macromolecular structure of cellulose is relatively well elucidated. Our study is limited to the l-p phase since it is reported to be dominant over the I-a phase. 

The chain flexibility can be a function of temperature or solvent concentration and possible conformational changes in mesomorphic polymers have been both predicted by theoretical calculations and observed in experiment. The elastic chain model takes intrachain interactions into account in a very simple way but neglects fine details of macromolecular structure. We present some results within this model for liquid crystalline behaviour and finally... 

The synthesis and some thermal properties of three series of block copolymers comprising both main-chain and side-chain liquid-crystalline (LC) blocks in the same macromolecular structure are described. The former block is a semiflexible LC polyester (block B), and the latter is an LC polymethacrylate (block A) containing a variously substituted mesogenic unit. The two structurally different blocks were partly phase-separated within the glassy and LC states and underwent distinct phase transitions. Significant deviations of the transition enthalpies relative to those of the corresponding homopolymers suggest the occurrence of a more or less diffuse interphase which may depend on the nature of the mesophase formed. 

Figure 5 Toward applications of self-assembled DNA systems, (a) Attachment of different sized gold nanoparticles to DNA and self-assembly of antennae structures, (b) DNA origami can be modified with multiple aptamers to produce stronger bivalent protein interactions, (c) Viruses can be specifically arranged on DNA origami, (d) Nanoparticles functionalized with DNA can be assembled into highly crystalline networks, (e) Using DNA, a well-ordered macromolecular 3D crystalline lattice can be assembled.

Finally, this results in the formation of a macromolecular structure with the global crystallinity smaller than the one produced in extrusion through short capillaries. 

On the other hand, the mechanical properties also depend on the materials molecular composition and structure, i.e., intrinsic parameters. Intrinsic parameters are, for instance, chemical composition or constitution, configuration, conformation, chain cross section, entanglement molecular weight, free volume, chain stiffness, macromolecular mobility, crystallinity, and others [4, 16, 17]. Chain length and chain length distribution (or molecular weight M ) have a basic influence on mechanical properties, which is illustrated in Fig. 1.17. Three regions can be identified ... 

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