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  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 2267-2277 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pinacyanol in the presence of an excess of poly(L-glutamic acid) [polymer/dye ratio (P/D) 〉 10] exhibits different absorption spectra in the visible region when bound to the slightly charged polypeptide in the α-helical conformation or to the nearly completely dissociated polypeptide in the coillike conformation. These spectra reveal aggregation of the dye bound to the macromolecular chain in both conformations, although in the coillike one different kinds of aggregates may be present. Dye binding is accompanied by the appearance of CD bands in the visible region which are also different for the α-helical and the coillike conformations. The aggregates formed in the presence of the latter change slowly in time and seem to induce some conformational changes in the polypeptide chain. Furthermore, they have been found to be, at least partially, stable with respect to a subsequent reversal to the α-helical conformation. All results could be qualitatively interpreted assuming that in the coillike conformation, ordered regions exist along the chain as proposed by Krimm and Tiffany.
    Additional Material: 5 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1841-1844 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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  • 3
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electric permittivity of alfalfa virus particles in buffer solutions of three different concentrations at pH 7 was studied between 10 kHz and 100 MHz. The experimental results could be described with one single dispersion curve of the Cole-Cole type characterized by a concentration independent specific dielectric increment and mean relaxation time. The results were interpreted semi-quantitatively in terms of counterions-atmosphere polarizability, neglecting counterion repulsion.
    Additional Material: 1 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 16 (1977), S. 33-41 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the presence of sodium poly(L-glutamate) at pH = 7.5 the dye pseudoisocyanine in dilute aqueous solution (Cd = 1.10 × 10-5 M) and low P/D values exhibits an absorption spectrum with a very sharp red-shifted J-band. Under the same conditions circular dichroism (CD) in the visible region is observed with an extremely sharp peak at the position of the J-band. At pH = 4.6, where the polypeptide is in the α-helix conformation, no such J-band is observed and no CD spectrum can be detected at the same P/D values. CD spectra in the uv range demonstrate that the occurrence of the dye-polypeptide complex which gives rise to the J-band at slightly alkaline pH is not accompanied by a conformational transition of the polypeptide towards the α-helical form.
    Additional Material: 4 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 4 (1966), S. 519-520 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 16 (1978), S. 641-651 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dielectric behavior of maleic acid-ethylene copolymer solutions has been investigated at different polymer concentrations and two degrees of neutralization α′. It is shown that this behavior is analogous to that of ordinary polyacids. Also the experimental data can be explained in terms of the van der Touw-Mandel theory, but at low α′ a possible contribution from motion of negative charges (in turn related to bound proton fluctuations) has to be taken into account. The dielectric results suggest that the formation of intramolecular hydrogen bonds has an influence on the change of the average dimensions of the chain with increasing α′. This seems to be confirmed by viscosity data.
    Additional Material: 4 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 773-781 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dielectric relaxation behavior of three sodium polyphosphates with different but low degrees of polymerization in aqueous solution (without salt) has been investigated between 8 kHz and 100 MHz. The highest molecular weight sample (DP 338) exhibits two dispersion regions as is generally observed with synthetic polyelectrolytes at higher degrees of polymerization and is interpreted, according to the theory of van der Touw and Mandel, by attributing a certain flexibility to the polymer chain. The experimentally determined relaxation time of the high-frequency dispersion is in fair agreement with the theoretically calculated value. For the lowest molecular weight sample (DP 112) the experimental results can best be described by a single dispersion curve pointing to a rigid, more or less stretched, conformation of the polyion in agreement with theoretical predictions. For the sample of intermediate molecular weight (DP 198) the situation is borderline as it is possible to describe the relaxation behavior by either one or two dispersion regions; it is, however, concluded from an analysis of the dielectric results that the average conformation is rather extended, but not completely rigid.
    Additional Material: 1 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 56 (1962), S. S23 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 23 (1957), S. 241-245 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: It seems that the dielectric properties of high polymer solutions may be partially attributed to an interaction between the macromolecules and the molecules of solvent, if the latter is polar. The study of the variations of the static dielectric constant with the temperature yields interesting data. By applying a model analogous to that proposed by Fröhlich for pure liquids to a dilute solution of a polar macromolecule in a polar solvent, a correlation factor (g) may be defined if the deformation polarization is considered macroscopically through the refractive index of the solutions. This treatment is valid as well in the case of rigid macromolecules as in the case where these chains are decomposed in statistical segments. The example of a 2% solution of polybutylmethacrylate in toluene shows that this effect indeed exists. The study of these properties, which is now going on, will show if a relation exists between the factor g for different solutions of high polymer in different solvents, particularly with respect to an eventual precipitation temperature.
    Notes: Il semble possible d'attribuer partiellement les propriétés diélectriques de solutions de hauts polymères à une interaction entre la macromolécule et les molécules du solvant, si ce dernier est polaire. L'étude de la variation de la constante diélectrique statique avec la température peut alors apporter des renseignements intéressants. Appliquant à la solution diluée d'une macromolécule polaire dans un solvant polaire, un modèle analogue à celui proposé par Fröhlich pour les liquides purs, on peut définir un facteur de corrélation (g) si l'on tient compte de la polarisation de déformation d'une façon macroscopique à travers l'indice de réfraction de la solution. Le raisonnement est valable aussi bien pour le cas où l'on considère la macromolécule comme un tout plus ou moins rigide que pour celui où on la décompose en chaǐnons statistiques. L'exemple d'une solution à 2% de polyméthacrylate de butyle dans le toluène montre que l'effet existe. I'étude de ces propriétés, commencée depuis peu au laboratoire, aura e.a. pour but de voir s'il existe une relation entre le facteur g pour différentes solutions de hauts polymères dans différents solvants, notamment par rapport à une éventuelle température de précipitation.
    Additional Material: 1 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 80 (1964), S. 141-148 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Konformationsumwandlung von teilweise veresterter Polymethacrylsüre wurde mit Hilfe der potentiometrischen Titration untersucht.Es wurde gefunden, daß die Stabilität der bei kleinem Dissoziationsgrad (α) vorliegenden Form nicht vermindert wird, wenn die Zahl jener Kettenglieder, die intramolekulare Wasserstoffbrücken ausbilden können, abnimmt. Es zeigt sich vielmehr, daß die Umwandlung mit der mittleren Ladung pro Struktureinheit zusammenhängt. Dies stützt die Hypothese, wonach die bei kleinen α-Werten stabile Form eine kompaktere Struktur besitzt, die möglicherweise durch VAN DER WAALsche Wechselwirkungen zwischen den  - CH3-Gruppen stabilisiert ist.
    Notes: The conformational transition of poly-(methacrylic acid), partially esterified with dimethyl sulfate, has been studied using potentiometric titration at constant temperature.It is found that the stability of the form existing at low values of dissociation (α) is not decreased by reducing the number of groups on the chain capable of establishing intramolecular hydrogen bonds. The transition is also shown to depend on the average charge per monomeric unit. This confirms the hypothesis that the stable form at low α-values is a compact structure stabilized probably by VAN DER WAALS attractions between  - CH3 groups.
    Additional Material: 6 Ill.
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