Zusammenfassung
Liquid microjets are inherently unstable and can be
broken into droplets by various means including
modulation of pressure, velocity, and/or fluid properties. In
this presentation, we discuss the controlled breakup of
viscous microjets via thermal modulation of surface
tension. Such modulation has been implemented using
CMOS/MEMS technology by integrating resistive heating
elements around each orifice of a manifold as depicted in
Fig. 1. When the heating elements are electrically pulsed,
the thermal energy they produce penetrates the surface of
the microjet, and is carried downstream to produce a spatial
variation of surface tension along the length of the jet,
which ultimately causes breakup and drop formation (Figs.
1 and 2). Using this process, microfluidic devices have been
fabricated with thousands of individually modulated
microjets that can produce steady steams of picoliter-sized
droplets at kilohertz frequency rates 1. In this presentation
we review methods for analyzing such devices.
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