Randomly Charged Polymers: Excess Charge Dependence of Spatial Configurations
نویسندگان
چکیده
Spatial configurations of randomly charged polymers, known as polyampholytes (PAs), are very sensitive to the overall excess charge Q. Analytical arguments, supported by Monte Carlo simulations and exact enumeration studies, lead to the following picture: For Q < Qc ≈ q0 √ N (q0 is the elementary charge, N is the number of monomers in the polymer), the radius of gyration Rg of the polymer decreases with decreasing temperature T and the polymer becomes compact, while for Q > Qc the polymer stretches with decreasing T . At low T , the dense states are described by Debye–Hückel theory, while the expanded states resemble a necklace of globules connected by strings. At such temperatures, the transition between the dense and the expanded states with increasing Q, is reminiscent of the breakup of a charged drop.
منابع مشابه
Instabilities of charged polyampholytes.
We consider polymers formed from a (quenched) random sequence of charged monomers of opposite signs. Such polymers, known as polyampholytes (PAs), are compact when completely neutral and expanded when highly charged. We examine the transition between the two regimes by Monte Carlo simulations, and by analogies to charged drops. We find that the overall excess charge, Q, is the main determinant ...
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