Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore.
Proc Natl Acad Sci U S A. 2011 Apr 12;108(15):5996-8. doi: 10.1073/pnas.1019623108. Epub 2011 Mar 29.
One way to focus the diffuse energy of a sound field in a liquid is by acoustically driving bubbles into nonlinear oscillation. A rapid and nearly adiabatic bubble collapse heats up the bubble interior and produces intense concentration of energy that is able to emit light (sonoluminescence) and to trigger chemical reactions (sonochemistry). Such phenomena have been extensively studied in bulk liquid. We present here a realization of sonoluminescence and sonochemistry created from bubbles confined within a narrow channel of polydimethylsiloxane-based microfluidic devices. In the microfluidics channels, the bubbles form a planar/pancake shape. During bubble collapse we find the formation of OH radicals and the emission of light. The chemical reactions are closely confined to gas-liquid interfaces that allow for spatial control of sonochemical reactions in lab-on-a-chip devices. The decay time of the light emitted from the sonochemical reaction is several orders faster than that in the bulk liquid. Multibubble sonoluminescence emission in contrast vanishes immediately as the sound field is stopped.
将声场的弥散能量聚焦在液体中的一种方法是通过声驱动气泡进入非线性振荡。气泡的快速且几乎绝热的坍塌会加热气泡内部，并产生能够发光（声致发光）和引发化学反应（声化学）的强烈能量集中。这种现象已经在大量液体中得到了广泛的研究。我们在这里展示了一种通过限制在基于聚二甲基硅氧烷的微流控装置的狭窄通道内的气泡来实现的声致发光和声化学。在微流道中，气泡形成平面/饼状。在气泡坍塌期间，我们发现了 OH 自由基的形成和光的发射。化学反应被紧密限制在气液界面内，这允许在微流控芯片设备中对声化学反应进行空间控制。从声化学反应中发射的光的衰减时间比在液体中快几个数量级。相比之下，多泡声致发光发射会随着声场的停止而立即消失。
