Ordered Structure in Solution

It has been predicted by theory that the polyelectrolyte stars can form different kinds of ordered structures in solutions at high concentrations. Likos et al. [93,94] pointed out the different crystal structures for polyelectrolyte stars with certain arm numbers and densities (see Fig. 11). This has been used to explain the anomalous structure with the concentrated polyelectrolyte star solutions. Ishizu et al. [95] successfully demonstrated this ordering by small angle X-ray scattering (SAXS) for concentrated PAA star solutions with arm number 30 and 97 (displayed in Fig. 12). No such phenomenon was seen for the polyelectrolyte star polymers under scrutiny here. The reason for this may be located in the finite polydispersity of the present systems that may suppress the formation of ordered phases. 

7 Inter-Poly electrolyte Complexes of Poly electrolyte Stars 

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Predict which of the following polyamino acids will form a helices and which will form no ordered structures in solution at room temperature. 

At the same time, Poddar and Forsman (13) have studied dilute solutions of the same polymer in a number of solvents by the methods of light scattering, osmometry and gel permeation chromatography. They have found evidence that an ordered structure in solution is disrupted by strong polymer + solvent interactions. Poddar and Forsman assume a parentage relationship between chain conformations in the solid state and in solution since the... 

In general, polysaccharides can exist in two conformational forms - random coils and ordered structures. In solutions, polysaccharides are expected to adopt random coil conformation since many flexible glycosidic linkages between the units in the polysaccharide chain allow rotation to occur around the glycosidic bonds involving little change in internal energy of the... 

Circular dichroism (CD) spectrometry is a useful tool for determining an ordered structure in solution. The ferrocene 4a exhibits an induced CD... 

As is true for many cellulose derivatives, hydroxypropylcellu-lose is able to form an ordered structure in solution when the polymer concentration is above a certain critical concentration. HPC/water solutions were studied over a wide range of concentrations, and the ordered structure which appears above a concentration C of about 40 % by weight was found to be cholesteric as is the case for all liquid crystalline cellulose derivative solutions studied until now. Upon heating, isotropic and cholesteric solutions undergo a phase transition at about 40 C. This new phase is turbid, and it is called "white suspension" or "white gel The critical concentration is not sensitive to temperature... 

The analysis of the data presented in the literatnre [50-66] indicates that pure water does not always satisfy the reqnirements expected of lubricating substances. Hence, there is a need to utilize appropriate additives that would reduce motion resistance and wear, prevent seizure, inhibit the corrosive action of water, and increase the viscosity of water. Surfactants can be used as such substances, primarily due to their adsorptivity at the interface and their ability to produce ordered structures in solutions. 

Because biomolecules normally exist in liquid water, this article will be largely concerned with their ordered structures in aqueous media and therefore with hydration effects. In order to understand better the influence of solute-solvent interactions on molecular order, also solvation in organic liquids will be considered to some extent. 

Hashimoto T., Shibayama M., and Kawai H., Ordered structure in block copolymer solution. 4. Scaling rules on size of fluctuations with block molecular weight, concentration temperature in segregation and homogeneous regimes. Macromolecules, 16, 1093, 1983. 

Matsuoka, H. and Ise> N. Small-Angle and Ultra-Small Angle Scattering Study of the Ordered Structure in Polyelectrolyte Solutions and Colloidal Dispersions. VoL 114, pp. 187-232. 

On the other hand, basic myelin protein and monomeric melittin are proteins which, by many criteria, are devoid of ordered structure in aqueous solutions. This results in freedom of rotation of tryptophan residues which are exposed to the solvent. Such a situation may exist for peptides without regular structure and for denatured proteins. 

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