基于声表面波微液滴并行加热研究

摘要

A new method for heating droplets in parallel was presented. An interdigital transducer and a reflector were fabricated on a 128° yx-LiNbO3 substrate using microelectrical technology. A poly( dimethylsiloxane) microcell filled with mineral oil was mounted on the piezoelectric substrate. A pattern with multi heating zones was designed and transferred to a copper sheet with the thickness of 0.3 millimeters using laser cutting. The copper sheet was then placed on the microcell with mineral oil. Surface acoustic wave was generated by applying an electrical signal to the interdigital transducer,and the acoustic energy was radiated into the mineral oil. Droplets on the heating zones at the end of the copper sheet were then heated due to heat transfer. Experiments results show that multi droplets can be heated in parallel,and their temperature variation is increased with the electrical signal power. The volume and the number of droplets to be heated in parallel do also affect their temperature variation.%提出了一种并行加热微液滴的方法。在128°旋转Y切割X传播方向的LiNbO3压电基片上采用微电子工艺制作叉指换能器和反射栅，在其声路径上贴合环形聚二甲基硅氧烷( PDMS)微槽，其内充满石蜡油微流体。设计有多个受热区的图案，经过激光切割转移到导热性良好的、厚度为0.3 mm的铜金属传热片上，并放置于PDMS微槽上。射频电信号加到叉指换能器上激发声表面波，辐射入微槽中的石蜡油微流体，并将能量通过传热片传递到受热区，进而加热受热区上的微液滴。以纯净水微液滴为实验对象，进行了多个微液滴并行加热实验。结果表明，在单个叉指换能器上加电信号激发的声表面波可同时加热多个微液滴，且其温度变化值随射频电信号功率增加而增加，同时，微液滴体积和受热区中并行加热的微液滴数影响其温度变化。