On-chip micro-droplet dispenser with disposable structure

We succeeded in dispensing micro-droplet by a disposable on-chip inkjet mechanism. Novelty of this paper is summarized as follows. (1) We employed a glass bonded PDMS to obtain leaf spring structure whose spring coefficient is 14 times of the conventional PDMS chip. As a result, we succeeded in dispensing of droplets by vibrating the membrane using the piezoelectric actuator attached to the PDMS disposable chip. (2) The nozzle for droplet dispensing was fabricated by SU-8 to obtain the hydrophobic surface which prevents any undesired satellite droplets produced. Consequently the accuracy of position of the droplet dispensing was achieved ±5 μm. The size of the droplet produced from the disposable nozzle (diameter = 100 μm) was in the range of 95-105 μm at the applied voltage of 105 V.