基于声表面波实现数字微流体的产生

Generating Digital Micro-Fluids Based on Surface Acoustic Waves

数字微流体的产生是压电材料为基片的微流控芯片进行微流分析的前提,报道了在压电基片上应用声表面波技术产生数字微流体的方法。在128°旋转Y切割X传播方向的LiNbO3基片上集成PDMS微通道,在微通道出口一侧为经疏水处理的铝薄片,注射泵产生恒定流量的微流体经PDMS微通道到达铝薄片并聚集,当聚集的微流体体积足够大时,微流体克服表面张力作用下滑到达压电基片,并在中心频率为27.7MHz叉指换能器激发的声表面波作用下输运,实现微流体的数字化。同时,理论分析了微流体在铝薄片表面上受力状况,并以水为实验对象,进行微流体数字化实验,结果表明,声表面波作用下能精确产生微升量级数字微流体,为压电微流控芯片提供了一种新的微流体引入方法。

It is necessary for Lab-on-a-chip with piezoelectric substrate to generate digital micro-fluids.A new method to generate digital micro-fluids based on surface acoustic waves has been presented.An interdigital transducers （IDT） with 27.7 MHz center frequency is fabricated on 127.68° YX-LiNbO3 substrate by micro-electric technology and a PDMS micro-channel,of which working surface is stuck on an aluminium thin slice and then coated by Teflon AF 1 600,is integrated onto the substrate.Micro-fluids can pass through the PDMS micro-channel and aggregate on the thin aluminium slice when a constant-rate of flow is given by ejector jet pump.After the micro-fluid with enough volumes has slide off the aluminium thin slice,SAW excited by the IDT drives the micro-fluid and finishes digital process.Force analysis of the micro-fluid has been accomplished and generating experiments of water digital micro-fluid have also been done.Results demonstrate that digital micro-fluid with micro-liter volume can be generated using surface acoustic wave,which is useful for Lab-on-chips with piezoelectric substrate.