화학공학소재연구정보센터
Rheologica Acta, Vol.58, No.9, 573-590, 2019
Investigating the dynamics of droplet breakup in a microfluidic cross-slot device for characterizing the extensional properties of weakly-viscoelastic fluids
A microfluidic device, deemed the Plateau-Rayleigh microfluidic extensional rheometer (PRIMER), is presented that uses a cross-slot geometry to observe a two-phase droplet-breakup event in which the viscoelastic fluid is in the dispersed (or droplet) phase. For viscoelastic fluids, we report that a cylindrical filament forms between droplet segments with a diameter that decays exponentially in time. In optically tracking this decay, both transient extensional viscosity and extensional relaxation times can be evaluated. For validating and optimizing the device, a range of poly(ethylene oxide) (PEO) solutions and Newtonian solutions were tested. Comparisons of the evolution profiles as a result of the presence of elasticity are made, and these results are compared with the results from dripping-onto-a-substrate (DoS), another emerging extensional technique.