New Method of Measuring Surface Tension Coefficient Based on Microfluidic Chip

A new method to measure surface tension coefficient using microfluidic chip is proposed and the fabrication process of microfluidic chip was conducted. Taking the polycarbonate track-etched (PCTE) membrane as the template, the pores were filled with PDMS (polydimethylsiloxane) prepolymer via capillarity-driven. After bonding with microchamber, microposts array was released by dissolving the membrane in organic solvent. When the surface tension balance was broken due to evaporation, the tips of the microposts array submerged in aqueous solvent were pulled and displaced at the liquid-air interface. By processing the microposts’ deformation images, the surface tension coefficient could be calculated. The experiment results show that the proposed method is effective and the measurement resolution can reach in the order of nN/μm.