ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Dielectric relaxation studies in the frequency range 100 Hz to 2 MHz of poly(γ-benzyl-L-glutamate) in dioxane have been carried out over a range of concentration 10-4-10-2g/g. The structure of aggregates is analyzed in terms of dipole moment and relaxation time. A critical concentration (≃ 10-3 g/g for the studied molecular weights) has been determined below which the aggregates are found to have linear head to tail type structure. Above the critical concentration a different structure of aggregates is apparent which could not be fully analyzed by these measurements alone. Possible forms of aggregation above the critical concentration are discussed. Formation of long range order which would lead to nematic liquid crystalline phase at higher concentrations has been discussed as one of the possible explanations for the observed behavior above the critical concentration.Maximum length of linear head to tail type aggregates for poly(γ-benzyl-L-glutamate) in dioxane as determined from these results correspond to an α-helix of molecular weight 210,000. A slight difference in the purity of dioxane has been shown to have an influence on the reproducibility of the state of aggregation as well as on the rate of disaggregation on dilution.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1976.360150809
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