论文标题：Inducing drop to bubble transformation via resonance in ultrasound

期刊：Nature Communications

作者：Duyang Zang, Lin Li, Wenli Di, Zehui Zhang, Changlin Ding, Zhen Chen, Wei Shen, Bernard P. Binks & Xingguo Geng

发表时间：2018/09/11

数字识别码：10.1038/s41467-018-05949-0

原文链接：https://www.nature.com/articles/s41467-018-05949-0?utm_source=Other_website&utm_medium=Website_links&utm_content=RenLi-MixedBrand-multijournal-Multidisciplinary-China&utm_campaign=ORG_USG_JRCN_RL_article_promotion_sciencenet_Sep_3rd

微信链接：https://mp.weixin.qq.com/s/zvdcXHODeqYEJTRCBO17_Q

一般来说，气泡破裂后会产生液滴，但《自然-通讯》本周的一篇论文Inducing drop to bubble transformation via resonance in ultrasound描述了一种逆向操作的方法——让液滴转变为气泡。这一研究成果有助于找到液-液界面的操纵方式，对软物质制造具有潜在的应用价值。

图1：声悬浮液滴从液滴到气泡的转变过程 图源：Zang 等

声悬浮能让液滴在声波作用下悬浮在空中，是液滴动力学研究的常用技术。声压可以把液滴压扁成很薄的液膜，并诱导屈曲现象，从而实现液滴的变形。

中国西北工业大学的臧渡洋及同事将这些已观察到的现象相结合，以对气泡的形成进行控制。作者先通过声辐射力将液滴压成薄片状的液膜，再通过超声场让液膜弯曲成碗状，内部为共振腔。作者发现，共振会让腔体扩大，并引导周围的液面弯曲，最后收缩成一个闭合的气泡（点击微信链接观看气泡形成过程）。

作者观察到的这一过程或指出了一条形成气泡的新途径——对于食品、化妆品及制药行业的泡沫制备具有潜在的应用价值。

摘要：Bubble formation plays an important role in industries concerned with mineral flotation, food, cosmetics, and materials, which requires additional energy to produce the liquid–gas interfaces. A naturally observed fact is, owing to the effect of surface tension, a bubble film tends to retract to reduce its surface area. Here we show a “reverse” phenomenon whereby a drop is transformed into a bubble using acoustic levitation via acoustic resonance. Once the volume of the cavity encapsulated by the buckled film reaches a critical value V*, resonance occurs and an abrupt inflation is triggered, leading to the formation of a closed bubble. Experiments and simulations both reveal that V* decreases with increasing acoustic frequency, which agrees well with acoustic resonance theory. The results afford enlightening insights into acoustic resonance and highlight its role in manipulating buckled fluid–fluid interfaces, providing a reference for fabricating unique core–shell-like materials.

阅读论文全文请访问：https://www.nature.com/articles/s41467-018-05949-0?utm_source=Other_website&utm_medium=Website_links&utm_content=RenLi-MixedBrand-multijournal-Multidisciplinary-China&utm_campaign=ORG_USG_JRCN_RL_article_promotion_sciencenet_Sep_3rd

期刊介绍：Nature Communications (https://www.nature.com/ncomms/) is an open access journal that publishes high-quality research from all areas of the natural sciences. Papers published by the journal represent important advances of significance to specialists within each field.

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（来源：科学网）