Model elastic liquids with water‐soluble polymers

The inertio-elastic planar entry flow of low-viscosity elastic fluids in micro-fabricated geometries

“…It is therefore not surprising that the geometric scale of microfluidic devices will become increasingly important with nonNewtonian fluids and result in flows (particularly those involving extension) that are different to those seen in the equivalent macro-scale experiment [2,3]. This is particularly relevant in high speed industrial processes such as roll-coating, electrospraying/spinning and inkjet printing in which the combination of high velocities and small lengthscales can result in the onset of appreciable elastic effects even in low viscosity aqueous polymer solutions [6].3 …”

“…For geometric lengthscales of l~O (10 µm), the ratio of molecular size/geometry is still 10 -5 . However, if we consider the mean radius of gyration of a PEO molecule with molecular weight 2µ10 6 g/mol (R g ~ N 1/2 b > 0.16 µm, where N is the number of Kuhn steps of size, b), the equivalent ratio (under equilibrium conditions)…”

Ultrasound‐modulated two‐fluid atomization of dilute polymer solutions

“…, G were found to be required when the experimental k k elastic and viscous moduli G X and G Y were simultaneously fitted to a series of Maxwell elements using nonlinear regres-Ž . sion Dontula et al, 1998 . Although the shortest predicted relaxation time is on the order of 5=10 y4 s, this has never been experimentally verified because moduli cannot be mea-Ž .…”

“…Although the shortest predicted relaxation time is on the order of 5=10 y4 s, this has never been experimentally verified because moduli cannot be mea-Ž . sured at high frequencies Dontula et al, 1998 . However, the ultrasonic atomization results reported in this article may provide empirical support of the predicted relaxation time, as will be described in the Results and Discussion section.…”

Hele-Shaw rheometry

“…and 0.06 wt. % polyethyleneoxide (PEO), 4 Â 10 6 g=mol: (both from Sigma-Aldrich) in water, as was also used by, among others, Dontula et al (1998) and Sankaran et al (2013).…”