Infrared laser-induced photothermal phase change for liquid actuation in microchannels

Localized fluid manipulation in microfluidic device is a key operation to various on-chip analytical/synthetic applications. In this work, we demonstrated the localized fluid actuation in microchannels by the infrared laser-induced evaporation-condensation-coalescence photothermal phase change process. Visualized experiments were carried out to investigate the dynamic phase change process and accompanying interfacial behaviors. Effects of laser power, spot speed, channel structure and actuation distance were investigated. Results indicate the actuation speed can be tuned by the output laser power, and the flow direction in microchannels can be selected by the control of laser spot trajectory. Long distance actuation performance suggests that the flow speed decreases due to the increase of fluid volume and flow resistance. The photothermally induced phase change process provides the means of simple and efficient localized fluid manipulation with remarkable dynamic response and the ability of agile maneuver in microfluidic channels, which could be further applied in different application scenarios.

Automated summary

This study demonstrates localized fluid manipulation in microchannels using infrared laser-induced phase change process, investigating dynamic behaviors and effects of laser power, spot speed, and channel structure. Results show that actuation speed can be tuned by laser power, and flow direction can be controlled by laser spot trajectory. Long distance actuation performance is affected by fluid volume and flow resistance, providing efficient fluid manipulation in microfluidic channels for various applications.