Spontaneous overcharging of macro-ion complexes
| Autor: | Robijn Bruinsma, William M. Gelbart, Stella Park |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
chemistry.chemical_classification
Quantitative Biology::Biomolecules Materials science General Physics and Astronomy Polyelectrolyte Ion Condensed Matter::Soft Condensed Matter symbols.namesake Classical mechanics Rigidity (electromagnetism) chemistry Chemical physics Colloidal particle symbols Counterion van der Waals force Entropic force |
| Zdroj: | Europhysics Letters (EPL). 46:454-460 |
| ISSN: | 1286-4854 0295-5075 |
| Popis: | Oppositely charged macro-ions—one of which is flexible and carries a larger total charge than the other—are expected on an energetic basis to assemble into neutral complexes which can aggregate due to attractive (e.g., van der Waals) interactions. We treat in this paper the counter-intuitive appearance of spontaneous overcharging in polyelectrolyte-colloid complexes, a phenomenon which has been observed in experiments and simulations involving flexible chains adsorbing on oppositely charged cores. We show that this overcharging can be accounted for in the Poisson-Boltzmann approximation; within this theory, overcharging is an entropic effect associated with release of the counterions of the highly charged polyelectrolyte chain as it "overwinds" onto the rigid colloidal particle. Increasing the rigidity of the polyelectrolyte chain leads eventually to undercharging of the complex. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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