Attraction between Like-Charged Macroions Mediated by Specific Counterion Configurations.
A Stelmakh1,2, W Cai3, A Baumketner4
1Department of Chemistry , Ivan Franko Lviv National University , 6 Kyrylo and Mefodii Street , Lviv 79005 , Ukraine.
The Journal of Physical Chemistry. B
|October 29, 2019
Summary
Like-charged macroions attract via specific counterion arrangements, a novel electrostatic mechanism. This finding is crucial for understanding biological processes and advancing industrial applications like catalysis.
Area of Science:
- Physical Chemistry
- Colloid Science
- Statistical Mechanics
Background:
- Like-charged macroions typically repel due to electrostatic forces.
- Understanding macroion interactions is vital for biology, chemistry, physics, and industry (e.g., ion extraction, catalysis).
Purpose of the Study:
- To report a novel mechanism for attraction between like-charged macroions.
- To investigate the role of counterion configurations in mediating this attraction.
- To explore the electrostatic nature and implications of this phenomenon.
Main Methods:
- Utilizing an implicit solvent model with a distance-dependent dielectric constant.
- Analyzing the potential of mean force to identify attractive interactions.
- Simulating specific configurations of macroions and counterions.
Main Results:
- A novel attraction mechanism between like-charged macroions at high ionic strength was identified.
- Specific counterion configurations between macroions were found to be statistically probable.
- The attraction strength correlates with macroion charge, confirming its electrostatic origin.
- The implicit solvent model qualitatively captures the thermodynamics of macroion dimers.
Conclusions:
- Specific counterion arrangements can induce attraction between like-charged macroions, challenging conventional understanding.
- This electrostatic mechanism is relevant for both model colloidal systems and potentially small chemical compounds like fullerenes.
- The findings have implications for controlling macroion self-assembly and designing advanced materials.
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