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Repulsion between oppositely charged rod-shaped macromolecules: Role of overcharging and ionic confinement
Hanne S Antila1, Paul R Van Tassel2, Maria Sammalkorpi1
1Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University, 00076 Aalto, Finland.
The Journal of Chemical Physics
|October 2, 2017
Summary
Charge asymmetry can induce repulsion between oppositely charged macro-ions in solutions. This study explores how varying ion charges and sizes influences these complex interactions.
Area of Science:
- Physical Chemistry
- Colloid and Surface Chemistry
- Computational Physics
Background:
- Understanding macro-ion interactions is crucial for fields like nanotechnology and biomolecular science.
- Charge asymmetry in macro-ion systems can lead to counterintuitive repulsive forces.
Purpose of the Study:
- To investigate the role of charge asymmetry in the interaction between oppositely charged rod-like macro-ions.
- To elucidate the mechanisms driving repulsion and attraction under varying ionic conditions.
Main Methods:
- Utilized Monte Carlo simulations based on the primitive model.
- Analyzed interactions considering rod charge/size and micro-ion valence/size/concentration.
Main Results:
- Repulsion can be induced by overcharging rods with asymmetric micro-ions.
- Asymmetric rod charges in symmetric micro-ion solutions can cause repulsion via osmotic pressure or attraction via ion "squeezing out".
Conclusions:
- Charge asymmetry significantly impacts macro-ion interactions, enabling repulsion.
- Findings advance the understanding of polyelectrolytes, nanotubes, and biomolecular systems.
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