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Ion-Modulated Ostwald Ripening Dynamics of Nitrogen Nanobubble Pairs
Xiangdang Guo1, Pengchao Zhang1,2, Chao Sun1,2,3
1Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing100084, China.
Journal of the American Chemical Society
|July 22, 2026
Summary
Electrolyte ions significantly impact nanobubble stability by altering water structure and gas diffusion. This study reveals an ion-modulated mechanism explaining nanobubble coarsening rates across different conditions.
Area of Science:
- Physical Chemistry
- Materials Science
- Computational Science
Background:
- Nanobubble stability is crucial for applications, but ion effects on coarsening are poorly understood.
- Microscopic mechanisms governing nanobubble Ostwald ripening require further investigation.
Purpose of the Study:
- To investigate how electrolyte ions influence bulk nanobubble stability and coarsening dynamics.
- To elucidate the microscopic mechanisms behind ion-modulated nanobubble ripening.
Main Methods:
- Machine-learning molecular dynamics simulations were employed.
- Ostwald ripening of nanobubbles was simulated under various conditions (neutral, acidic, alkaline, saline).
Main Results:
- Nanobubble ripening rates followed the order: acidic > alkaline ≈ pure water > saline.
- Counterions were found to regulate interfacial water and ion orientation via hydration and electrostatic effects.
- Saline conditions showed enriched ion pairs forming dense hydration layers, impacting gas diffusion and ripening.
Conclusions:
- An ion-modulated microscopic mechanism, based on enthalpy-entropy balance and specific-ion effects, explains observed ripening rates.
- Findings bridge atomistic interfacial restructuring with thermodynamic principles for nanobubble dynamics.
- This work provides a physicochemical framework for understanding ion-influenced nanobubble coarsening.
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