ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
A previously reported phase diagram of polyelectrolyte solutions as functions of degree of polymerization and the concentration is improved. The new phase diagram is also intended for salt-free solutions of polyelectrolytes with the constitutional repeating unit -C-CX-, X being a charged group. The main improved point is the crossover concentrations between the dilute and semidilute regimes in the low concentration range of less than 10−2 mol/l, which is based on the recent most reliable experimental data on the persistence length of flexible polyion chains. This phase diagram as well introduces both the concentrated regime, which has been not only theoretically predicted but also experimentally confirmed, and the experimentally newly found swollen regime. Furthermore, it is proposed that the dilute regime is separated into four regions, gaslike, poor order, liquidlike order and crystal. The degrees of orderliness in these regions have been assumed to depend on the ratio δ/ξcent of the amplitude of thermal fluctuations to the mean intermolecular distance. Typically, δ/ξcent=1/5 as the critical Lindemann ratio of melting is assigned for the crossover between the liquidlike order and crystal regions. Interestingly, the most probable region for the formation of a 3-D lattice is located within the experimental approach. © 2001 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1408296
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