Strong transient flows generated by thermoplasmonic bubble nucleation

TL;DR

This paper presents a method to generate and measure strong, transient microfluidic flows driven by vapor bubble nucleation on plasmonic nanoantennas, enabling high-speed, high-throughput fluid actuation.

Contribution

It introduces a robust technique for producing and quantifying intense flow transients caused by vapor bubble nucleation on isolated plasmonic nanoantennas, with detailed analysis of flow dynamics.

Findings

Peak flow speeds reach mm/s in water.

Flow modulation rates up to 100 Hz.

Transient flows originate from rapid bubble expansion.

Abstract

The challenge of inducing and controlling localized fluid flows for generic force actuation and for achieving efficient mass transport in microfluidics is key to the development of next generation miniaturized systems for chemistry and life sciences. Here we demonstrate a methodology for the robust generation and precise quantification of extremely strong flow transients driven by vapor bubble nucleation on spatially isolated plasmonic nanoantennas excited by light. The system is capable of producing peak flow speeds of the order mm/s at modulation rates up to 100 Hz in water, thus allowing for a variety of high-throughput applications. Analysis of flow dynamics and fluid viscosity dependence indicate that the transient originates in the rapid bubble expansion that follows nucleation rather than being strictly thermocapillary in nature.