Radial oscillation and translational motion of a gas bubble in a micro-cavity

Zhang, Xianmei; Li, Fan; Wang, Chenghui; Guo, Jianzhong; Mo, Runyang; Hu, Jing; Shi, Chengming; He, Jiaxin; Liu, Honghan

doi:10.1016/j.ultsonch.2022.105957

Cited by 6 publications

(6 citation statements)

References 37 publications

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“…This behavior, here experimentally observed, has been only recently theoretically predicted. [27] This result confirms that the biomimetic microchambers can be a fundamental tool to gain further insights into fluid dynamics phenomena that involve confinement in deformable microstructures. [30][31][32][33] A clear advantage of our approach is the possibility of modifying the design of the microchambers (shape and dimensions) to investigate these phenomena in different conditions.…”

Section: Discussionsupporting

confidence: 68%

“…[26] After the nucleation at these sites, the bubble is expected to move to the center of the microchamber with a characteristic time scale of 1 μs, too short to be captured by our set-up. [17,27] After a time of the order of 100 ms the bubble migrates to the center of the membrane and pins to it. It is newsworthy to note that sometimes, during its migration, the bubble splits, leaving a smaller bubble behind, which then disappears (Figure S3, Supporting Information).…”

Section: How Microchamber Dimensions Affect the Biomimetic Behaviormentioning

confidence: 99%

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Cavitation‐driven Deformable Microchambers Inspired by Fast Microscale Movements of Ferns

Montagna,

Palagi,

Naselli

et al. 2023

Adv Funct Materials

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Annulus cells of fern sporangia spontaneously deform driven by water transpiration and cavitation, resulting in the peculiar macroscale catapult‐like movement of the sporangium. Annulus cells' behavior, if artificially replicated, can inspire a novel class of fast actuators composed of annulus‐mimicking units. However, the transpiration and cavitation‐driven dynamics observed in annulus cells is never reproduced. Here, prismatic microcavities are assembled with a polydimethylsiloxane (PDMS) microfilm to realize artificial microchambers that mimic the annulus cells, replicating for the first time their evaporation‐driven collapse and their fast return triggered by the nucleation of bubbles. The microchambers, in turn, can be fabricated in adjacency, resulting in bending arrays driven by transpiration. Working with an artificial system allows this study to investigate the fluidic phenomena arising from the interplay of a soft, semi‐permeable membrane with a micro‐confined liquid bounded by rigid walls. First, the microchambers aspect ratio influences the membrane dynamics and the bubble shape (either spherical or non‐spherical). Second, the growth rate of the bubble interplay with the membrane in the expansion dynamics. This study's results demonstrate the artificial replication of annulus cells' behavior, offering a plant‐like solution to realize fast, microscale movements, and a novel tool to investigate complex fluidic mechanisms involving micro‐confined cavitation.

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Section: Discussionsupporting

confidence: 68%

Section: How Microchamber Dimensions Affect the Biomimetic Behaviormentioning

confidence: 99%

Cavitation‐driven Deformable Microchambers Inspired by Fast Microscale Movements of Ferns

Montagna,

Palagi,

Naselli

et al. 2023

Adv Funct Materials

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“…It has been demonstrated that the friction reaction between PTFE and a semiconductor can achieve environmental pollutant degradation . Previous reports have also shown that polymers, especially PTFE, can withdraw electrons from water during the liquid–solid contact electrification process. ,, That is, ultrasound can drive the rapid and large radial oscillation of bubble radii, and any PTFE particles attached to the bubble will undergo similar stretching and contraction cycles. The viscous friction generated between the PTFE and water during these cycles may cause the electron clouds of PTFE and H 2 O to overlap and reduce the potential barrier .…”

Section: Results and Disscussionmentioning

confidence: 99%

O₂-Independent H₂O₂ Production via Water–Polymer Contact Electrification

Wang,

Wei,

Shen

et al. 2023

Environ. Sci. Technol.

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Hydrogen peroxide (H 2 O 2 ), as a critical green chemical, has received immense attention in energy and environmental fields. The ability to produce H 2 O 2 in earth-abundant water without relying on low solubility oxygen would be a sustainable and potentially economic process, applicable even to anaerobic microenvironments, such as groundwater treatment. However, the direct water to H 2 O 2 process is currently hindered by low selectivity and low production rates. Herein, we report that poly(tetrafluoroethylene) (PTFE), a commonly used inert polymer, can act as an efficient triboelectric catalyst for H 2 O 2 generation. For example, a high H 2 O 2 production rate of 24.8 mmol g cat −1 h −1 at a dosage of 0.01 g/L PTFE was achieved under the condition of pure water, ambient atmosphere, and no sacrificial agents, which exceeds the performance of state-of-the-art aqueous H 2 O 2 powder catalysts. Electron spin resonance and isotope experiments provide strong evidence that water−PTFE tribocatalysis can directly oxidize water to produce H 2 O 2 under both anaerobic and aerobic conditions, albeit with different synthetic pathways. This study demonstrates a potential strategy for green and effective tribocatalytic H 2 O 2 production that may be particularly useful toward environmental applications.

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“…Cavitation has been investigated for many years, and various models have been developed to describe the motion of bubbles in aqueous media, [1][2][3] near a rigid surface [4] and in a liquid cavity. [5,6] In recent years, ultrasonic cavitation has emerged in various medical applications as a way to influence matter noninvasively. The cavitation effects have been widely investigated and employed in different medical treatments, such as ablation of tumors, [7] fractionation of calculi [8] or tissue, [9] enhancement of permeability of cells for drug delivery, [10] non-invasive surgery, [11] contrast in ultrasound enhanced imaging, [12] and reversible opening of blood-brain barrier.…”

Section: Introductionmentioning

confidence: 99%

Bubble nucleation in spherical liquid cavity wrapped by elastic medium

Zhang

Wang

et al. 2023

Chinese Phys. B

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According to classical nucleation theory, gas nuclei can generate and grow into a cavitation bubble when the liquid pressure exceeds a threshold. However, classical nucleation theory is not including boundary effects. An enclosed spherical liquid cavity surrounding by elastic medium is introduced to model the nucleus process in tissue. Based on the equilibrium pressure relationship of a quasi-static process, the expressions of the threshold and the modified nucleation rate is derived by considering of the tissue elasticity. It is shown that the constrains plays an important role in the nucleus process. There is a positive correlation between that nucleation threshold pressure and constrains, which can be enhanced by an increasing tissue elasticity and decreasing size of the cavity. Meanwhile, temperature is found to be a key parameter of nucleus process, and cavitation is more likely to occur in confined liquids with temperature T > 100℃. In contrast, less impacts are induced by these factors, such as bulk modulus, liquid cavity size and acoustic frequency. Although these theoretical predictions of the thresholds have been demonstrated by many previous literatures, much lower thresholds can be obtained in liquids containing dissolved gases, e, g. the nucleation threshold is about -21 MPa in a liquid of 0.8 nm gas nuclei at room temperature. Moreover, when there is a gas nucleus of 20 nm, the theoretical threshold pressure might be less than 1 MPa.

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Radial oscillation and translational motion of a gas bubble in a micro-cavity

Cited by 6 publications

References 37 publications

Cavitation‐driven Deformable Microchambers Inspired by Fast Microscale Movements of Ferns

Cavitation‐driven Deformable Microchambers Inspired by Fast Microscale Movements of Ferns

O₂-Independent H₂O₂ Production via Water–Polymer Contact Electrification

Bubble nucleation in spherical liquid cavity wrapped by elastic medium

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Radial oscillation and translational motion of a gas bubble in a micro-cavity

Cited by 6 publications

References 37 publications

Cavitation‐driven Deformable Microchambers Inspired by Fast Microscale Movements of Ferns

Cavitation‐driven Deformable Microchambers Inspired by Fast Microscale Movements of Ferns

O2-Independent H2O2 Production via Water–Polymer Contact Electrification

Bubble nucleation in spherical liquid cavity wrapped by elastic medium

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Product

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O₂-Independent H₂O₂ Production via Water–Polymer Contact Electrification