Microfluidic mixing driven by dual eccentrically focused surface acoustic waves

IF 4.1 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Sensors and Actuators A-physical Pub Date : 2025-04-23 DOI:10.1016/j.sna.2025.116600

Jin-Chen Hsu, Kai-Li Liao

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引用次数: 0

Abstract

In this study, we present enhanced micromixing driven by dual eccentrically focused surface acoustic waves (DEF-SAWs). The DEF-SAWs are excited by two eccentrically arranged, coplanar, focused interdigital transducers (IDTs) patterned on the surface of a 500 μm-thick piezoelectric lithium-niobate (LiNbO₃) substrate. These two focused SAW beams can deliver concentrated acoustic energy into a circular chamber-embedded microchannel to generate enhanced encircling stirring. Compared with using the conventional straight channel, we demonstrate that the circular chamber-embedded channel is more suitable for accommodating the encircling circulation flow induced by Eckart streaming and prolongs the working time for mixing. Hence, the joint action of Rayleigh–Schlichting streaming and Eckart streaming achieves high mixing efficiency. We construct a series of finite element models and conduct simulations to elucidate the working mechanisms of encircling acoustic pressure and encircling-enhanced mixing behaviors induced by DEF-SAW fields. Subsequently, we fabricate DEF-SAW micromixers using standard photolithography and replica molding of a master mold created by micro-milling. The continuous flow mixing experiments verify the enhanced mixing efficiency, and submicron-particle flow visualization experiments confirm the encircling effect. Additionally, mixing performance using higher acoustic frequencies supported by acoustic plate modes of the LiNbO₃ substrate in the DEF-SAW devices is also investigated and compared.

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双偏心聚焦表面声波驱动的微流控混合

在这项研究中，我们提出了双偏心聚焦表面声波（DEF-SAWs）驱动的增强微混合。def - saw由两个偏心排列的共面聚焦数字间换能器（idt）在500 μm厚的铌酸锂（LiNbO3）压电衬底上激发而成。这两个聚焦的声表面波束可以将集中的声能传递到圆形腔室嵌入的微通道中，以产生增强的环形搅拌。结果表明，与传统的直线型通道相比，圆形内嵌腔通道更适合容纳由Eckart流引起的环形循环流动，并延长了混合的工作时间。因此，Rayleigh-Schlichting流和Eckart流的共同作用达到了很高的混合效率。我们构建了一系列有限元模型并进行了仿真，以阐明DEF-SAW场诱导的环绕声压和环绕增强混合行为的工作机制。随后，我们使用标准光刻和通过微铣削创建的主模具的复制成型制造DEF-SAW微混合器。连续流混合实验验证了混合效率的提高，亚微米颗粒流动可视化实验证实了围合效果。此外，还研究和比较了在DEF-SAW器件中使用LiNbO3衬底的声板模式支持的更高声波频率的混合性能。

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来源期刊

Sensors and Actuators A-physical 工程技术-工程：电子与电气

CiteScore

8.10

自引率

6.50%

发文量

630

审稿时长

49 days

期刊介绍： Sensors and Actuators A: Physical brings together multidisciplinary interests in one journal entirely devoted to disseminating information on all aspects of research and development of solid-state devices for transducing physical signals. Sensors and Actuators A: Physical regularly publishes original papers, letters to the Editors and from time to time invited review articles within the following device areas: • Fundamentals and Physics, such as: classification of effects, physical effects, measurement theory, modelling of sensors, measurement standards, measurement errors, units and constants, time and frequency measurement. Modeling papers should bring new modeling techniques to the field and be supported by experimental results. • Materials and their Processing, such as: piezoelectric materials, polymers, metal oxides, III-V and II-VI semiconductors, thick and thin films, optical glass fibres, amorphous, polycrystalline and monocrystalline silicon. • Optoelectronic sensors, such as: photovoltaic diodes, photoconductors, photodiodes, phototransistors, positron-sensitive photodetectors, optoisolators, photodiode arrays, charge-coupled devices, light-emitting diodes, injection lasers and liquid-crystal displays. • Mechanical sensors, such as: metallic, thin-film and semiconductor strain gauges, diffused silicon pressure sensors, silicon accelerometers, solid-state displacement transducers, piezo junction devices, piezoelectric field-effect transducers (PiFETs), tunnel-diode strain sensors, surface acoustic wave devices, silicon micromechanical switches, solid-state flow meters and electronic flow controllers. Etc...