Polyelectrolyte complexes toroid

The method is then applied to the study of global and local structure of polyelectrolyte chains, as well as the distribution of counterions and condensation. We also explain the morphologies (globular, rod, toroid, etc.) of polyelectrolyte complexes as a consequence of the chain stiffness itself. 

As the stiffness of the polyelectrolyte chains is increased, the polyplexes tend to adopt structures such as toroids or rods [28, 29] but, independently of the morphology of the resulting structures, the forces driving the complexation process are similar as has been reviewed by Bloomfield [30, 31]. As for the flexible polyelectrolytes, an important contribution to the overall driving force for condensation of stiff polyelectrolytes is the increased entropy associated with the release of counterions from the polyelectrolytes in the exchange reaction. 

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