Comparative study of static and dynamic wetting properties of liquid-liquid phase in PMMA microfluidic T-shaped device

Abstract

Microfluidics plays a vital role in modern technologies. Microfluidics has large and widespread applications especially in the field of bio-medical science, enhancing the reaction rates, chemical synthesis, electro chromatography and drug screening. The purpose of this research is to interrelate the wetting dynamic property at micro level in T-junction of a Poly methyl methacrylate (PMMA) channel to the static property at macro scale, as the dynamic property measurement at micro level is quite arduous. The experimental study of oil-water system was performed on micro and macro level. Formation of droplets were carried out in PMMA microchip using passive methodology and visualized with the help of camera mounted microscope. The sizes of these droplets were calculated by image processing. Fabrication of T junction microchip was performed by surface activation method. In the micro device the water droplet (dispersed medium) were formed in the vegetable oil (continuous medium) and the effect of different concentration of TWEEN 80 surfactant was studied. On the macro level the critical concentration of surfactant was measured by means of interfacial-tension between oil and water interface and contact-angle variation. While at micro level the effect of surfactant on droplet length was varied exponentially with its concentration then a breakeven point of surfactant amount was observed after which no significant change in wetting property was found. It was inferred that the wetting properties in microfluidic device can be characterized by the support of macro scale measurements.