Characterization of Constant Flow-Driven Microfluidic Oscillator

Development of microfluidic circuits that are analogous to electronic circuits is useful because of their potential to drastically reduce dynamic off-chip controllers. In microfluidic circuits, a microfluidic oscillator that converts constant input to pulsatile output is the key component. Here, we apply a constant inflow to our previous constant pressure-driven oscillator and demonstrate its distinct behavior. The outflow of the oscillator has a pulse-duration period (T
_D
) and a pulse-rest period (T
_R
) at a low inflow rate of 20-120 μL/min. In this range of inflow rates, the pulse number of T
_D
increased, and T
_R
decreased. In each T
_D
, the maximum value of each pulse sequentially decreased. On the other hand, at a high inflow rate of 140-260 μL/min, the oscillator produced a continuous sawtooth pulsatile flow without T
_R
. Our theoretical model reveals that average increase and decrease rates of the inlet pressure are critical parameters for determining the output pulse behaviors. Our study is useful and provides a foundation for developing microfluidic circuits using the electrofluidic analogy.