THE DYNAMIC INTERFACIAL TENSION EFFECT ON THE GAS-LIQUID INTERFACE BREAKUP IN A MICROCHANNEL FLOW FOCUSING DEVICE

The varied interfacial tension caused by the unsaturated adsorption of the surfactants on bubble interface is proposed in recent years. We present an experimental study of the Hydrogen bubble breakup in the SDS (Sodium dodecyl sulfate) solutions in a microchannel flow-focusing device. The dynamic process is captured by high-speed camera and analysed through the neck point motion on the gaseous thread interface during the bubble pinch-off period. The interface geometry and evolution during the non-linear breakup period show a great difference between two SDS concentrations, which one is lower than the CMC (critical micelle concentration) and another is higher. However, the static surface tension of the two SDS solution only has 15% difference. The dynamics interfacial tension is proved to have a vital effect on the bubbles breakup in the microchannel when the surfactants concentration higher than the CMC.