Multiple temporal scale investigation of growth dynamics of plasmonic bubbles

INTRODUCTION: Professor Yuliang Wang from Beihang Universitys School of Mechanical Engineering and Automation,and Professor Detlef Lohse from the University of Twente in the Netherlands, together with their collaborators have recently made progress in the formation mechanism and growth dynamics of plasmonic bubbles. By applying an ultra-high speed imaging technique, they were able to study bubble growth dynamics across multiple temporal scales (ns –> s). The results have been published in prestigious journals includingthe Proceedings of the National Academy of Sciences, USA(PNAS) and ACS Nano.  

Microbubble formation induced by plasmonic effects of noble metal nanostructures under resonant illumination is of great importance for many plasmonic-enhanced processes, including solar energy harvesting, cell therapy, biomedical photothermal imaging, and micro/nanoscale manipulation and manufacturing. As a result, the investigation of bubble nucleation mechanism and growth dynamics is gaining more and more attention in the field.

Professor Yuliang Wang investigated the dynamics of plasmonic bubble nucleation,and together with researchers from the Netherlands and Canada, captured the growth dynamics of plasmonic bubbles with a temporal resolution up to nanosecond using an ultra-high speed imaging technique.They revealed, for the first time, the four phases of bubble growth, as shown in Fig 1.  

Fig 1. Four phases of plasmonic bubble evolution under the continuous laser irradiation on the patterned gold nanoparticle surface in water

In Phase I, the research team found that after a short delay time τd of laser illumination, a giant bubble was nucleated at the solid-liquid interface of a gold nanoparticle decorated sample surface (Fig 2). The nucleated giant bubbles, which are termed as initial giant bubbles, show distinct behaviors compared with the ordinary plasmonic bubbles. The giant bubbles collapse after about 10 microseconds and their growth speed is about 2000 times higher than the ordinary ones. With the thermal diffusion and spinodal decomposition being considered, the mechanism of the giant bubble nucleation was systematically revealed. The results have been published in the Proceedings of the National Academy of Sciences, USA (PNAS).

Fig 2. Temporal evolution of an initial giant bubble

The collapse of the giant bubbles was followed by the nucleation of several sequential oscillating bubbles (Phase II). The plasmonic bubbles were then stabilized and entered Phase III and Phase IV,in which the plasmonic bubbles exhibited distinct growth dynamics. Models were developed to explain the growth dynamics of plasmonic bubbles in the two phases. The results show that the growth of the plasmonic bubbles was dominated by the vaporization only within the first 10 ms (Fig 3, Phase III). After that, the process was mainly dominated by the diffusion of the dissolved gas in water (Fig 3, Phase IV). The results indicate that the dissolved gas plays a significant role in the growth of the plasmonic bubbles, which was not realized in the previous studies of plasmonic bubbles. The results have been published in the journal ACS Nano.  

Fig 3. The illustration of bubble growth dynamics for air rich and partially degassed water

The research was conducted across multiple temporal scales from nanosecond to second. It provides a comprehensive understanding of the temporal evolution of plasmonic bubbles in the vicinity of laser spot at solid-liquid interfaces. The findings on plasmonic bubble dynamics, as well as the role of dissolved gas plays during the process, have strong bearings on various applications of plasmonic bubbles, notably on medical applications.

Yuliang Wang, associate professor, school of mechanical engineering and automation, Beihang University, E-mail: wangyuliang@buaa.edu.cn

References

[1]Yuliang Wang*, Mikhail E. Zaytsev, Guillaume P.R. Lajoinie, Hai Le The, Jan C.T. Eijkel, Albert van den Berg, Michel Versluis, Bert M. Weckhuysen, Xuehua Zhang, Harold J.W. Zandvliet and Detlef Lohse*, Giant and Explosive Plasmonic Bubbles by Delayed Nucleation, Proceedings of the National Academy of Sciences, 2018, 115(30):7676-7681.

[2]Yuliang Wang*, Mikhail Zaytsev, Hai Le The, Jan Eijkel, Harold Zandvliet, Xuehua Zhang*, and Detlef Lohse*, Vapor and gas bubble growth dynamics around laser-irradiated water-immersed plasmonic nanoparticles. ACS Nano, 2017, 11(2):2045-2051.