School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749, South Korea.
J Colloid Interface Sci. 2011 Oct 15;362(2):567-74. doi: 10.1016/j.jcis.2011.07.014. Epub 2011 Jul 18.
This paper reports a droplet-based microfluidic device composed of patterned co-planar electrodes in an all-in-a-single-plate arrangement and coated with dielectric layers for electrowetting-on-dielectric (EWOD) actuation of discrete droplets. The co-planar arrangement is preferred over conventional two-plate electrowetting devices because it provides simpler manufacturing process, reduced viscous drag, and easier liquid-handling procedures. These advantages lead to more versatile and efficient microfluidic devices capable of generating higher droplet speed and can incorporate various other droplet manipulation functions into the system for biological, sensing, and other microfluidic applications. We have designed, fabricated, and tested the devices using an insulating layer with materials having relatively high dielectric constant (SiO(2)) and compared the results with polymer coatings (Cytop) with low dielectric constant. Results show that the device with high dielectric layer generates more reproducible droplet transfer over a longer distance with a 25% reduction in the actuation voltage with respect to the polymer coatings, leading to more energy efficient microfluidic applications. We can generate droplet speeds as high as 26 cm/s using materials with high dielectric constant such as SiO(2).
本文报道了一种基于液滴的微流控器件，它由图案化的共面电极组成，采用全板单层布置，并涂有介电层，用于电润湿（EWOD）驱动离散液滴。与传统的两板式电润湿器件相比，共面布置具有更简单的制造工艺、更小的粘性阻力和更简单的液体处理程序。这些优势使得更通用和高效的微流控器件能够产生更高的液滴速度，并能够将各种其他液滴操作功能集成到系统中，用于生物、传感和其他微流控应用。我们使用具有相对较高介电常数（SiO2）的绝缘层设计、制造和测试了这些器件，并将结果与具有低介电常数的聚合物涂层（Cytop）进行了比较。结果表明，具有高介电层的器件在更长的距离上能够更可重复地转移液滴，并且与聚合物涂层相比，驱动电压降低了 25%，从而实现了更节能的微流控应用。我们可以使用具有高介电常数的材料（如 SiO2）产生高达 26 cm/s 的液滴速度。
