关键词: 声表面波, 微流控技术, 等离子体活化键合, 聚二甲基硅氧烷, 铌酸锂

Abstract: Acoustofluidic chip technology finds extensive applications in biomedicine, environmental monitoring, and other fields, with microparticle separation representing a primary use case. A key fabrication approach for such chips involves the heterogeneous integration of polydimethylsiloxane (PDMS) microchannels and lithium niobate resonators. However, the core challenge is overcoming liquid leakage at the interface resulting from inadequate bond strength. To this end, conventional radio-frequency plasma source was substituted with high-density microwave source, which enabled high-trength plasma-activated bonding between PDMS and lithium niobate. Leakage tests demonstrated that the maximum flow rate of the fabricated acoustofluidic chip increased by 125%, reaching 270 µL/min. This establishes a critical foundation for high-throughput operation in acoustofluidic devices. Furthermore, the integration of fluid handling, thermal control, electrical actuation, and imaging modules with the chip enabled the creation of a precision acoustofluidic system for microparticle separation. The system was employed to successfully separate polystyrene microparticles of 3 µm and 5 µm diameters, achieving separation efficiencies of 79.4% and 89.5%, respectively.

Key words: surface acoustic wave, microfluidic technology, plasma-activated bonding, polydimethylsiloxane, lithium niobate