Droplet generation via a single bubble transformation in a nanofluidic channel

Here we report the first demonstration on droplet generation from the transformation of a single bubble in a nanofluidic channel by a laser-induced jet. A viscous two-dimensional Rayleigh-Plesset-type model is derived to describe the bubble dynamics in the nanofluidic channel, which accounts for the effect of shear stresses from the channel wall. The droplet generation (number and volume) is investigated experimentally by controlling the jet velocity via laser energy and distance. This study expands the understanding of jetting in the nanofluidic channel and demonstrates a novel method for femtoliter-volume single or multiple droplet formation. It is envisioned that this work will open new doors in on-demand generation of nanodroplets.