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Formation of Salt Bonds in Polyampholyte Chains
Author(s) -
Moldakarimov Samat B.,
Kramarenko Elena Yu.,
Khokhlov Alexei R.,
Kudaibergenov Sarkyt E.
Publication year - 2001
Publication title -
macromolecular theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 56
eISSN - 1521-3919
pISSN - 1022-1344
DOI - 10.1002/1521-3919(20011001)10:8<780::aid-mats780>3.0.co;2-q
Subject(s) - counterion , polyelectrolyte , chemistry , chain (unit) , chemical physics , ion , salt (chemistry) , polymer , polymer chemistry , organic chemistry , physics , astronomy
Abstract In this paper we study the influence of the formation of intrachain ion pairs (salt bonds) and the distribution of counterions on the behavior of single polyampholyte chains in a dilute solution. It has been shown that neutral polyampholyte chains can undergo jump‐like collapse transition from the swollen state to the globular state with the formation of ion pairs between oppositely charged ions of the chain. A polyampholyte chain with an excess charge shows the behavior of a conventional polyelectrolyte chain and counterions play an important role in the chain behavior. We distinguish three possible states of counterions: free counterions inside and outside the macromolecule, and a bound state of counterions forming ion pairs with the corresponding ions of the polymer chain. We found a non‐monotonous behavior of the chain upon increasing the excess charge on the chain: the chain swells from a compact state to elongated conformation and shrinks again to the compact state when the excess charge of the chain is increased.