Molecular insight into hydrogen bulk nanobubbles with external static electric fields

JP Yuan and SD Wang and HQ Wei and GQ Shu and JY Pan, PHYSICS OF FLUIDS, 37, 102010 (2025).

DOI: 10.1063/5.0293964

As an efficient and controllable modulation approach, external static electric fields (ESEFs) exhibit significant regulatory influences on gas-liquid interfacial dynamics, demonstrating considerable potential for manipulating nanobubble stability. Although ESEFs show promise for manipulating hydrogen bulk nanobubbles (BNBs), the fundamental mechanisms underlying their stability and evolution remain poorly understood. In this study, all-atom molecular dynamics simulations were conducted to investigate the effects of ESEFs (0-1.0 V/nm) on the stability and morphological evolution of hydrogen BNBs (4.8-6.6 nm in diameter). The results show that ESEFs induce uniform elongation of BNBs along the field direction, accompanied by progressive dissolution. Larger BNBs (e.g., 6.6 nm) exhibit superior stability, retaining over 58% of their initial hydrogen content at 0.5 V/nm. With increasing field strength, the aspect ratio of BNBs escalates to similar to 3.0, while hydrogen dissolution is markedly accelerated at 1.0 V/nm, yielding a 2.4-fold increase in dissolved hydrogen compared to that under field- free conditions. Mechanistic analysis indicates that ESEFs trigger the alignment of water dipoles, elevate intra-bubble pressure, and generate anisotropic electrostriction forces, collectively driving bubble deformation and dissolution. Energy analysis reveals that the ESEF sustains the deformation of the system by lowering the system energy and the surface energy of the BNB to overcome surface tension and drive the system into a more thermodynamically stable state. These findings demonstrate the significance of ESEFs in BNB behavior from microscopic levels, providing a theoretical foundation for the regulation of hydrogen BNBs in engineering such as nanofluidic systems and electrochemical devices.

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