Microfluidic devices are known for their accurate control of emulsification, but are less known for their suitability to investigate involved dynamic mechanisms. We previously showed that a microfluidic Y-junction can be used to measure interfacial tension in the millisecond time-scale, at high interface expansion rates, and under convective mass transport. In the present work, we further use this device to elucidate and compare dynamic adsorption behaviour of water- or oil-soluble surfactants, in combination with different alkanes. We found that oil viscosity affects adsorption of the oil-soluble surfactant Span 20 because surfactant transport is influenced by viscosity through the internal velocity. Conversely, adsorption of the water-soluble surfactant Tween 20 was not affected by oil viscosity. When comparing surfactant adsorption rates, it was clear that surfactant structure became more important when more surfactants were present at the interface; Tween 20 adsorption was slower than Span 20 because of steric repulsion at the interface.

微流体装置以其对乳化的精确控制而闻名，但因其适合研究所涉及的动力学机制而鲜为人知。我们以前表明微流控Y结可用于在毫秒级的时间尺度，高界面扩展率和对流传质下测量界面张力。在目前的工作中，我们进一步使用该装置来阐明和比较水溶性或油溶性表面活性剂与不同烷烃的动态吸附行为。我们发现油的粘度会影响油溶性表面活性剂Span 20的吸附，因为表面活性剂的传输受内部速度对粘度的影响。相反，水溶性表面活性剂吐温20的吸附不受油粘度的影响。比较表面活性剂的吸附率时，很明显，当界面上存在更多的表面活性剂时，表面活性剂的结构变得更加重要。由于界面处的空间排斥，吐温20的吸附速度比Span 20慢。