Velocity control of nanoliter droplets using a pneumatic dispensing system

This paper introduces a pneumatic dispensing system to control the velocity of nanoliter droplets with small variation of volume. The system consists of a flexible membrane integrated with a backflow stopper. This unique dispensing mechanism can control the velocity of droplets according to applied positive pressures regardless of other operating conditions and design parameters. The range of droplet velocities is shifted by the flow resistance at the outlet under the same cross-section area. Our dispensing system can eject droplets of desired volume at a velocity that can be easily controlled by selecting design parameters and operating conditions. This dispensing system will provide a reliable performance within an optimized condition stably to deposit droplets onto accurate locations.