Journal of Rheology

Superensembles of linear viscoelastic models of polymer melts

Sachin Shanbhag, Seung Joon Park, and Zuowei Wang
The idea of incorporating multiple models of linear rheology into a superensemble, to forge a consensus forecast from the individual model predictions, is investigated. The relative importance of the individual models in the so-called multimodel superensemble (MMSE) was inferred by evaluating their ... [J. Rheol. 56, 279 (2012)] published Thu Feb 2, 2012.

Three-dimensional flow of colloidal glasses

T. F. F. Farage and J. M. Brader
Recent experiments performed on a variety of soft glassy materials have demonstrated that any imposed shear flow serves to simultaneously fluidize these systems in all spatial directions [Ovarlez et al., Nature Mater. 9, 115119 (2010)]. When probed with a second shear flow, the viscous response of t ... [J. Rheol. 56, 259 (2012)] published Fri Jan 20, 2012.

Emergence of turbid region in startup flow of CTAB/NaSal aqueous solutions between parallel plates

Takehiro Yamamoto and Keisuke Taniguchi
The emergence of turbidity in startup flows of aqueous solutions of cetyltrimethylammonium bromide (CTAB)/sodium salicylate (NaSal) between parallel discs was investigated. An induction time and a critical shear rate required for the emergence of turbidity were measured for solutions of several mola ... [J. Rheol. 56, 245 (2012)] published Wed Jan 18, 2012.

Steady Couette flows of elastoviscoplastic fluids are nonunique

I. Cheddadi, P. Saramito, and F. Graner
The HerschelBulkley rheological fluid model includes terms representing viscosity and plasticity. In this classical model, below the yield stress the material is strictly rigid. Complementing this model by including elastic behavior below the yield stress leads to a description of an elastoviscoplas ... [J. Rheol. 56, 213 (2012)] published Fri Jan 13, 2012.

Elimination of inertia from a Generalized Langevin Equation: Applications to microbead rheology modeling and data analysis

Andres Cordoba, Tsutomu Indei, and Jay D. Schieber
SynopsisViscoelastic properties of condensed soft matter can be estimated by following the trajectory of an embedded micron-sized particle in a method called passive microbead rheology. Data analysis of passive microbead rheology is usually based on formulas that relate bead displacement statistics ... [J. Rheol. 56, 185 (2012)] published Thu Jan 12, 2012.

The matching of a one-dimensional numerical simulation and experiment results for low viscosity Newtonian and non-Newtonian fluids during fast filament stretching and subsequent break-up

M. Tembely, D. Vadillo, M. R. Mackley et al.
This paper develops a model for fast filament stretching, thinning, and break-up for Newtonian and non-Newtonian fluids, and the results are compared against experimental data where fast filament relaxation occurs. A 1D approximation was coupled with the arbitrary Lagrangian Eulerian (ALE) formulati ... [J. Rheol. 56, 159 (2011)] published Thu Dec 22, 2011.

Deformation and flow of matter: Interrogating the physics of materials using rheological methods

Gregory B. McKenna
Rheological measurements offer a unique means of interrogating the physics of amorphous solids, including crosslinked rubbers and polymeric glasses. Here, we present several vignettes to demonstrate the ability of both classical and novel rheological experiments to resolve important questions in con ... [J. Rheol. 56, 113 (2011)] published Wed Dec 21, 2011.

Liquid viscoelasticity probed by a mesoscale piezoelectric bimorph cantilever

Melissa L. Mather, Martin Rides, Crispin R. G. Allen et al.
The viscoelastic properties of fluids are key to their performance in industries ranging from biotechnology to the automotive industry. Traditionally, fluid viscoelastic properties are monitored with rheometers but these are expensive, require a skilled operator, function over a relatively limited f ... [J. Rheol. 56, 99 (2011)] published Tue Dec 20, 2011.

The effect of interfacial slip on the dynamics of a drop in flow: Part I. Stretching, relaxation, and breakup

Arun Ramachandran, Kostas Tsigklifis, Anshuman Roy et al.
Using a numerical method based on the boundary-integral technique, we assess the impact of interfacial slip on the dynamics of deformation and breakup of a single drop subjected to a uniaxial extensional flow under creeping-flow conditions. Interfacial slip is incorporated in our continuum developme ... [J. Rheol. 56, 45 (2011)] published Mon Dec 19, 2011.

Rheology of surface-modified titania nanoparticles dispersed in PDMS melts: The significance of the power law

Rose S. Ndong and William B. Russel
We investigated the rheology of titanium dioxide (TiO) nanoparticles with various surface modifications in neat and binary blends of polydimethylsiloxane (PDMS) homopolymers of different molecular weights (4 k77 k). The dispersions for bare, octadecyl-(C), and PDMS-grafted particles reflect differen ... [J. Rheol. 56, 27 (2011)] published Thu Dec 15, 2011.

A sequence of physical processes determined and quantified in large-amplitude oscillatory shear (LAOS): Application to theoretical nonlinear models

Simon A. Rogers and M. Paul Lettinga
The nonlinear yielding responses of three theoretical models, including the Bingham, a modified Bingham, and Giesekus models, to large-amplitude oscillatory shear are investigated under the framework proposed recently by Rogers et al. (2011). Under this framework, basis states are allowed to wax and ... [J. Rheol. 56, 1 (2011)] published Tue Nov 29, 2011.

Shear-induced phase separation (SIPS) with shear banding in solutions of cationic surfactant and salt

Prachi Thareja, Ingo H. Hoffmann, Matthew W. Liberatore et al.
The rheological behavior and microstructure of branched, cationic wormlike micellar (WLM) solutions of 40 mM erucyl bis(hydroxyethyl)methylammonium chloride (EHAC) are studied as a function of added salt (sodium salicylate) concentration, temperature, and shear rate via Rheosmall-angle light scatter ... [J. Rheol. 55, 1375 (2011)] published Thu Sep 29, 2011.

Evaluation of molecular linear viscoelastic models for polydisperse H polybutadienes

Si Wan Li, Heon E. Park, and John M. Dealy
Two tube-based molecular models, the hierarchical 3.0 model and the branch-on-branch model were evaluated for their abilities to predict the behavior of a series of polydisperse, H-shaped, 1,4-polybutadienes. The samples had been synthesized using a novel technique designed to suppress the generatio ... [J. Rheol. 55, 1341 (2011)] published Fri Sep 23, 2011.

Numerical predictions of the viscosity of non-Brownian suspensions in the semidilute regime

Genta Rexha and Mario Minale
The viscosity of a non-Brownian suspension in simple shear cannot be theoretically predicted in the limit of the semidilute approximation, since it depends on the initial configuration. Batchelor and Green [J. Fluid Mech. 56, 401427 (1972)] proved that the suspension viscosity can be expressed in po ... [J. Rheol. 55, 1319 (2011)] published Tue Sep 13, 2011.

Rotational diffusion may govern the rheology of magnetic suspensions

P. Kuzhir, C. Magnet, G. Bossis et al.
This paper is focused on the theoretical modeling of the rheological properties of the magnetic suspensions in shear flows under an external magnetic field aligned with the streamlines. The conventional theory postulates that the field-induced aggregates of magnetic particles are highly anisotropic ... [J. Rheol. 55, 1297 (2011)] published Wed Sep 7, 2011.

Effects of weak elasticity on the stability of high Reynolds number co- and counter-rotating Taylor-Couette flows

Cari S. Dutcher and Susan J. Muller
This study examines the impact of dilute polymer solutions on the unique isolated secondary flows between concentric, rotating cylinders, namely Taylor-Couette (TC) flow. We mapped the stability of flow states using Newtonian and dilute polyethylene oxide (PEO) solutions over the Reynolds number ran ... [J. Rheol. 55, 1271 (2011)] published Fri Sep 2, 2011.

Basic characteristics of uniaxial extension rheology: Comparing monodisperse and bidisperse polymer melts

Yangyang Wang, Shiwang Cheng, and Shi-Qing Wang
We have carried out continuous and step uniaxial extension experiments on monodisperse and bidisperse styrene-butadiene random copolymers (SBR) to demonstrate that their nonlinear rheological behavior can be understood in terms of yielding through breakdown of the chain entanglement network and rubb ... [J. Rheol. 55, 1247 (2011)] published Fri Sep 2, 2011.

Loss of solutions in shear banding fluids driven by second normal stress differences

S. Skorski and P. D. Olmsted
Edge fracture occurs frequently in non-Newtonian fluids. A similar instability has often been reported at the free surface of fluids undergoing shear banding and leads to expulsion of the sample. In this paper, the distortion of the free surface of such a shear banding fluid is calculated by balanci ... [J. Rheol. 55, 1219 (2011)] published Thu Aug 25, 2011.

Rheological properties of polymer composites with flexible fine fibers

Tadashi Yokohara, Shogo Nobukawa, and Masayuki Yamaguchi
Effect of the addition of polymeric fine fibers on the rheological properties is studied employing poly(lactic acid) PLA as a matrix. Fine fibers of poly(butylene terephthalate) PBT, whose melting point is higher than that of PLA, is prepared in a PLA matrix by melt-stretching with rapid cooling. Th ... [J. Rheol. 55, 1205 (2011)] published Thu Aug 25, 2011.

Hard vs soft constraints in the full field reconstruction of incompressible flow kinematics from noisy scattered velocimetry data

Monirosadat Sadati, Clarisse Luap, Martin Kroger et al.
High quality flow kinematics reconstruction from noisy and spatially scattered data requires the use of regularization techniques but remains a challenge. We set out to test the effect and practical relevance of additional incompressibility constraints. To this end, we present two methods for recons ... [J. Rheol. 55, 1187 (2011)] published Wed Aug 24, 2011.