基于声表面波技术实现微流体数字化

Digital Micro-fluids Generated by Surface Acoustic Waves

微流体的数字化是压电微流控芯片进行微流分析的前提,提出了采用声表面波(SAW)实现微流体数字化的方法。在128°YX-LiNbO3基片上研制了中心频率为27.7 MHz的叉指换能器,在压电基片上方固定一细针,它经由Teflon软管与注射泵相连,注射泵提供恒定流量的微流体到达细针孔端并聚集,当聚集的微流体高度达到细针孔端与压电基片间距时,叉指换能器激发的声表面波驱动微流体实现微流体数字化。提出了计算细针孔端与压电基片间距的方法和微流体实现数字化的条件。以水为实验对象进行数字化实验,结果表明,声表面波作用下能实现微流体数字化,为压电微流控芯片提供了一种新的微流体引入方法。

Generating digital micro-fluids is necessary for lab-on-a-piezoelectric-substrate to finish micro-fluidic analysis.A new method for generating digital micro-fluids based on surface acoustic waves was presented in this paper.Inter-digital transducer（IDT） with 27.7 MHz center frequency was fabricated on 128°YX-LiNbO3 substrate.A small needle was fixed upon the substrate with small distance and connected to an injection pump by Teflon soft tube.Micro-fluids were aggregated to the top of the needle when a constant-rate of flow was given by injection pump.As soon as the volume of aggregated micro-fluids was large so that the micro-fluid could touch with the piezoelectric substrate,the micro-fluid was split and moved along the substrate.The distance between the top of the needle and the substrate was calculated and an expression that micro-fluid could be generated was deduced.Experiments for generating water digital micro-fluids had been done.Results demonstrated that digital micro-fluid could be generated using surface acoustic wave.The work was useful for lab-on-chips with piezoelectric substrate.