Microfluidic rheology of non-Newtonian liquids.
We investigate the rheological properties of a non-Newtonian glass-former liquid within lithographically defined microchannels in the range of temperatures above the vitrification region. The non-Newtonian behavior of the fluid, as evidenced by rotational rheology, is well described by a power law dependence of the viscosity on the shear rate. Taking into account such non-Newtonian character in the equations for the microfluidic motion, we relate the penetration dynamics into capillaries with the liquid rheological properties. The temperature dependence of the viscosity, determined over 1 order of magnitude in the temperature range 286-333 K and for shear rates between 0.07 and 1 s-1, can be described by a Vogel-Fulcher-Tamman law, consistent with the fragile nature of the investigated compound. Microfluidics is a promising analytical approach for the investigation of the rheology of non-Newtonian fluids within confined microenvironments.
Girardo
Salvatore
S
NNL, National Nanotechnology Laboratory of CNR-INFM, Università degli Studi del Salento c/o Distretto Tecnologico ISUFI, via Arnesano, I-73100 Lecce, Italy.
Cingolani
Roberto
R
Pisignano
Dario
D
D044085:Microfluidics / Q000295:instrumentation / Q000379:methods*; D008962:Models, Theoretical; D012212:Rheology; D033081:Shear Strength; D013696:Temperature; D014783:Viscosity