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Nondestructive rheological measurements of biomaterials with a magnetic microwire rheometer J. Rheol. (IF 3.3) Pub Date : 2023-02-24 Margaret Braunreuther, Maude Liegeois, John V. Fahy, Gerald G. Fuller
Programmable hydrogels, such as thiolated hydrogels, are frequently used for tissue engineering and drug delivery applications, because they offer the ability to control gelation, degradation, and adhesion. Understanding how the mechanical properties of these materials change during these processes is essential as they directly impact cell fate and delivery efficacy. The rheology of hydrogels has been
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Microscopic activated dynamics theory of the shear rheology and stress overshoot in ultradense glass-forming fluids and colloidal suspensions J. Rheol. (IF 3.3) Pub Date : 2023-02-21 Ashesh Ghosh, Kenneth S. Schweizer
We formulate a particle and force level, activated dynamics-based statistical mechanical theory for the continuous startup nonlinear shear rheology of ultradense glass-forming hard sphere fluids and colloidal suspensions in the context of the elastically collective nonlinear Langevin equation approach and a generalized Maxwell model constitutive equation. Activated structural relaxation is described
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Tribological variable-friction coefficient models for the simulation of dense suspensions of rough polydisperse particles J. Rheol. (IF 3.3) Pub Date : 2023-02-16 Jose A. Ruiz-Lopez, Sagaya S. Prasanna Kumar, Adolfo Vazquez-Quesada, Juan de Vicente, Marco Ellero
The rheology of concentrated suspensions of particles is complex and typically exhibits a shear-thickening behavior in the case of repulsive interactions. Despite the recent interest arisen, the causes of the shear-thickening remain unclear. Frictional contacts have been able to explain the discontinuous shear thickening in simulations. However, the interparticle friction coefficient is considered
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Rheology of non-Brownian particle suspensions in viscoelastic solutions. Part 1: Effect of the polymer concentration J. Rheol. (IF 3.3) Pub Date : 2023-02-13 Anni Zhang, Eric S. G. Shaqfeh
We study the effect of varying polymer concentration, measured by the dimensionless polymer viscosity partition function β, on the steady shear rheology of rigid particle suspensions using direct numerical simulation of the Oldroyd-B model. We compare the bulk rheology using immersed boundary simulations at Φ=2.5% and 5% to body-fitted single-particle simulations and find that the per-particle viscosity
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Rheology of non-Brownian particle suspensions in viscoelastic solutions. Part II: Effect of a shear thinning suspending fluid J. Rheol. (IF 3.3) Pub Date : 2023-02-13 Anni Zhang, Eric S. G. Shaqfeh
The shear rheology of particle suspensions in shear-thinning polymeric fluids is studied experimentally using parallel plate measurements and numerically using fully resolved, 3D finite volume simulations with the Giesekus fluid model. We show in our experiments that the steady shear viscosity and first normal stress difference coefficient of the suspension evolve from shear-thickening to substantially
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Gaborheometry: Applications of the discrete Gabor transform for time resolved oscillatory rheometry J. Rheol. (IF 3.3) Pub Date : 2023-02-03 Joshua David John Rathinaraj, Gareth H. McKinley
Oscillatory rheometric techniques such as small amplitude oscillatory shear (SAOS) and, more recently, medium amplitude oscillatory shear and large amplitude oscillatory shear (LAOS) are widely used for rheological characterization of the viscoelastic properties of complex fluids. However, in a time-evolving or mutating material, the build-up or breakdown of microstructure is commonly both time- and
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On the nature of flow curve and categorization of thixotropic yield stress materials J. Rheol. (IF 3.3) Pub Date : 2023-01-27 Tulika Bhattacharyya, Alan R. Jacob, George Petekidis, Yogesh M. Joshi
Thixotropy is a phenomenon related to time dependent change in viscosity in the presence or absence of flow. The yield stress, on the other hand, represents the minimum value of stress above which steady flow can be sustained. In addition, the yield stress of a material may also change as a function of time. Both these characteristic features in a material strongly influence the steady state flow curve
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Confined Brownian suspensions: Equilibrium diffusion, thermodynamics, and rheology J. Rheol. (IF 3.3) Pub Date : 2023-01-23 Alp M. Sunol, Roseanna N. Zia
We examine the impact of confinement on the structure, dynamics, and rheology of spherically confined macromolecular suspensions, with a focus on the role played by entropic forces, by comparing the limits of strong hydrodynamics and no hydrodynamics. We present novel measurements of the osmotic pressure, intrinsic viscosity, and long-time self-diffusivity in spherical confinement and find confinement
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Particle migration of suspensions in a pressure-driven flow over and through a porous structure J. Rheol. (IF 3.3) Pub Date : 2023-01-20 Parisa Mirbod, Nina C. Shapley
Laboratory experiments were conducted to study particle migration and flow properties of non-Brownian, noncolloidal suspensions ranging from 10% to 40% particle volume fraction in a pressure-driven flow over and through a porous structure at a low Reynolds number. Particle concentration maps, velocity maps, and corresponding profiles were acquired using a magnetic resonance imaging technique. The model
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Dilute polymer solutions under shear flow: Comprehensive qualitative analysis using a bead-spring chain model with a FENE-Fraenkel spring J. Rheol. (IF 3.3) Pub Date : 2023-01-13 I. Pincus, A. Rodger, J. Ravi Prakash
Although the nonequilibrium behavior of polymer solutions is generally well understood, particularly in extensional flow, there remain several unanswered questions for dilute solutions in simple shear flow, and full quantitative agreement with experiments has not been achieved. For example, experimental viscosity data exhibit qualitative differences in shear-thinning exponents, the shear rate for the
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Complex polymer topologies in blends: Shear and elongational rheology of linear/pom-pom polystyrene blends J. Rheol. (IF 3.3) Pub Date : 2023-01-13 V. Hirschberg, S. Lyu, M. G. Schußmann
The shear and elongational rheology of linear and pom-pom shaped polystyrene (PS) blends was investigated experimentally and modeled using constitutive models such as the Doi–Edwards and the molecular stress function (MSF) model. The pom-pom molecule is the simplest topology to combine shear thinning with strain hardening in elongational flow. A PS pom-pom with a self-entangled backbone (Mw,bb = 280 kg mol−1)
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Viscous dissipation in large amplitude oscillatory shear of unsaturated wet granular matter J. Rheol. (IF 3.3) Pub Date : 2023-01-12 Ahmad Awdi, Camille Chateau, Franc̨ois Chevoir, Jean-Noël Roux, Abdoulaye Fall
The present work investigates nonlinear behavior in large amplitude oscillatory shear (LAOS) of unsaturated wet granular materials using pressure-imposed rheometric measurements that enable to explore how the material properties characterizing the flow response depend on both strain amplitude and frequency of deformation. Away from the quasistatic limit, we show that the energy dissipated per unit
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On the startup behavior of wormlike micellar networks: The effect of different salts bound to the same surfactant molecule J. Rheol. (IF 3.3) Pub Date : 2023-01-10 Rossana Pasquino, Pietro Renato Avallone, Salvatore Costanzo, Ionita Inbal, Dganit Danino, Vincenzo Ianniello, Giovanni Ianniruberto, Giuseppe Marrucci, Nino Grizzuti
We report on shear startup data for two wormlike micellar solutions, differing only in concentration and type of two binding aromatic sodium salts. The surfactant molecule is cetylpiridinium chloride at a fixed concentration (100 mM). Sodium salicylate (NaSal) and diclofenac sodium (Diclo) are used as binding salts at concentrations 68 mM NaSal and 52 mM Diclo such that both systems are fully entangled
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Instant yield stress measurement from falling drop size: The “syringe test” J. Rheol. (IF 3.3) Pub Date : 2023-01-09 A. Geffrault, H. Bessaies-Bey, N. Roussel, P. Coussot
We analyze different flow regimes of a filament formed by extrusion of a material through a cylindrical die. We deduce that the elongational yield stress of a simple yield stress fluid (i.e., with negligible thixotropy effects) can be determined from the mass of the droplet after filament breakage and an estimation of the critical radius at pinch-off at the solid-liquid regime transition. We demonstrate
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Universal flow-induced orientational ordering of colloidal rods in planar shear and extensional flows: Dilute and semidilute concentrations J. Rheol. (IF 3.3) Pub Date : 2023-01-09 Byoungjin Chun, Hyun Wook Jung
The design of flow processes to build a macroscopic bulk material from rod-shaped colloidal particles has drawn considerable attention from researchers and engineers. Here, we systematically explore and show that the characteristic strain rate of the flow universally determines the orientational ordering of colloidal rods. We employed the fluctuating lattice Boltzmann method by simulating hydrodynamically
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Understanding the transient large amplitude oscillatory shear behavior of yield stress fluids J. Rheol. (IF 3.3) Pub Date : 2023-01-09 Krutarth M. Kamani, Gavin J. Donley, Rekha Rao, Anne M. Grillet, Christine Roberts, Abhishek Shetty, Simon A. Rogers
A full understanding of the sequence of processes exhibited by yield stress fluids under large amplitude oscillatory shearing is developed using multiple experimental and analytical approaches. A novel component rate Lissajous curve, where the rates at which strain is acquired unrecoverably and recoverably are plotted against each other, is introduced and its utility is demonstrated by application
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A thermodynamically consistent constitutive equation describing polymer disentanglement under flow J. Rheol. (IF 3.3) Pub Date : 2022-12-07 Benjamin E. Dolata, Peter D. Olmsted
We derive a thermodynamically consistent framework for incorporating entanglement dynamics into constitutive equations for flowing polymer melts. We use this to combine the convected constraint release (CCR) dynamics of Ianniruberto–Marriccui into a finitely extensible version of the Rolie–Poly model, and also include an anisotropic mobility as in the Giesekus model. The reversible dynamics are obtained
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Improving stretchability of associative polymers through tuning density of the secondary interactionsa) J. Rheol. (IF 3.3) Pub Date : 2022-12-07 Shilong Wu, Huanhuan Yang, Quan Chen
The macroscopic stretchability of ionomer melts strongly relies on the structural evolution during the elongational flow. It has been noted that the introduction of the secondary associations weaker than the ionic association can improve the stretchability. To understand the mechanism, this study examines the stretchability of unentangled ionomers containing a fixed number of ionic groups per chain
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Non-affine motion and selection of slip coefficient in constitutive modeling of polymeric solutions using a mixed derivative J. Rheol. (IF 3.3) Pub Date : 2022-11-21 D. Nieto Simavilla, P. Español, M. Ellero
Constitutive models for the dynamics of polymer solutions traditionally rely on closure relations for the extra stress or related microstructural variables (e.g., conformation tensor) linking them to flow history. In this work, we study the eigendynamics of the conformation tensor within the GENERIC framework in mesoscopic computer simulations of polymer solutions to separate the effects of nonaffine
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Flow-concentration coupling determines features of nonhomogeneous flow and shear banding in entangled polymer solutions J. Rheol. (IF 3.3) Pub Date : 2022-11-17 Michael C. Burroughs, Yuanyi Zhang, Abhishek Shetty, Christopher M. Bates, Matthew E. Helgeson, L. Gary Leal
Shear banding in entangled polymer solutions is an elusive phenomenon in polymer rheology. One recently proposed mechanism for the existence of banded velocity profiles in entangled polymer solutions stems from a coupling of the flow to banded concentration profiles. Recent work [Burroughs et al., Phys. Rev. Lett. 126, 207801 (2021)] provided experimental evidence for the development of large gradients
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Understanding the rheology of kaolinite clay suspensions using Bayesian inference J. Rheol. (IF 3.3) Pub Date : 2022-11-17 Ranjiangshang Ran, Shravan Pradeep, Sébastien Kosgodagan Acharige, Brendan C. Blackwell, Christoph Kammer, Douglas J. Jerolmack, Paulo E. Arratia
Mud is a suspension of fine-grained particles (sand, silt, and clay) in water. The interaction of clay minerals in mud gives rise to complex rheological behaviors, such as yield stress, thixotropy, and viscoelasticity. Here, we experimentally examine the flow behaviors of kaolinite clay suspensions, a model mud, using steady shear rheometry. The flow curves exhibit both yield stress and rheological
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FSVPy: A python-based package for fluorescent streak velocimetry (FSV) J. Rheol. (IF 3.3) Pub Date : 2022-11-16 Han Lin, Brendan C. Blackwell, Connor C. Call, Shanliangzi Liu, Claire Liu, Michelle M. Driscoll, Jeffrey J. Richards
Predictive constitutive equations that connect easy-to-measure transport properties (e.g., viscosity and conductivity) with system performance variables (e.g., power consumption and efficiency) are needed to design advanced thermal and electrical systems. In this work, we explore the use of fluorescent particle-streak analysis to directly measure the local velocity field of a pressure-driven flow,
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Micronewton shear rheometer performing SAOS using 2 mg of sample J. Rheol. (IF 3.3) Pub Date : 2022-11-16 Weiwei Wu, Jintian Luo, Xikai Ouyang, Wangjing He, Kangle Bao, Hui Li
Rheological measurements typically require at least 20–50 mg of sample. We set up a miniaturized sliding-plates shear rheometer (mgRheo) that requires only 2 mg sample or even less. We designed a flexure-based force-sensing device that could measure force ranging from the micronewton to millinewton scale, e.g., 40 μN–400 mN for one particular spring constant. The setup was strain-controlled by a piezostage
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Fractal structures of PA6/POE blend nanocomposites and their dynamic properties J. Rheol. (IF 3.3) Pub Date : 2022-11-15 Milad Hadaeghnia, Shervin Ahmadi, Ismaeil Ghasemi, Paula M. Wood-Adams
We investigate the effect of minor phase rheological properties and compatibilizer on the phase morphology and graphene 3D structure in polyamide-6 (PA6)/polyolefin elastomer (POE) blends. It is revealed that in blends containing low viscosity (LV) POE, graphene is better dispersed facilitating its localization at the interface. In the blend containing high viscosity (HV) POE with poor graphene dispersion
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Role of micellar entanglements on kinetics of shear banding flow formation J. Rheol. (IF 3.3) Pub Date : 2022-11-14 Peter Rassolov, Hadi Mohammadigoushki
We investigate the effects of micellar entanglement number on the kinetics of shear banding flow formation in a Taylor–Couette flow. Three sets of wormlike micellar solutions, each set with a similar fluid elasticity and zero-shear-rate viscosity, but with varying entanglement densities, are studied under the startup of steady shear. Our experiments indicate that in the set with low fluid elasticity
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Viscoelasticity and rheological hysteresis J. Rheol. (IF 3.3) Pub Date : 2022-11-10 Shweta Sharma, V. Shankar, Yogesh M. Joshi
Rheological characterization of complex fluids subjected to cyclic shear-rate sweep often exhibits hysteresis. Since both viscoelastic and thixotropic materials show hysteresis loops, it is important to understand distinguishing features (if any) in the same shown by either. Lately, there has been substantial work that attempts to relate the area enclosed by the hysteresis loop with the manner in which
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Strain softening of natural rubber composites filled with carbon black and aramid fiber J. Rheol. (IF 3.3) Pub Date : 2022-11-10 Zhaopeng Hu, Junwei Zhou, Yihu Song, Qiang Zheng, Wanjie Wang
Engineered rubber vulcanizates may contain a low content of short fibers and a high content of nanoparticles while the effects of the different fillers on the softening behavior are not yet explored. Herein, influences of carbon black (CB) and short aramid fiber (AF) on the Payne and Mullins effects of natural rubber composites are investigated for the first time by creating master curves of dynamic
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Shear thickening in dense bidisperse suspensions J. Rheol. (IF 3.3) Pub Date : 2022-11-09 Nelya Malbranche, Bulbul Chakraborty, Jeffrey F. Morris
Discrete-particle simulations of bidisperse shear thickening suspensions are reported. The work considers two packing parameters, the large-to-small particle radius ratio ranging from δ=1.4 (nearly monodisperse) to δ=4, and the large particle fraction of the total solid loading with values ζ=0.15, 0.5, and 0.85. Particle-scale simulations are performed over a broad range of shear stresses using a simulation
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Shear viscosity for finitely extensible chains with fluctuating internal friction and hydrodynamic interactions J. Rheol. (IF 3.3) Pub Date : 2022-11-09 R. Kailasham, Rajarshi Chakrabarti, J. Ravi Prakash
An exact solution of coarse-grained polymer models with fluctuating internal friction and hydrodynamic interactions has not been proposed so far due to a one-to-all coupling between the connector vector velocities that precludes the formulation of the governing stochastic differential equations. A methodology for the removal of this coupling is presented, and the governing stochastic differential equations
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Polymer threadings and rigidity dictate the viscoelasticity of entangled ring-linear blends and their composites with rigid rod microtubules J. Rheol. (IF 3.3) Pub Date : 2022-11-09 Karthik R. Peddireddy, Ryan Clairmont, Rae M. Robertson-Anderson
Mixtures of polymers of varying topologies and stiffnesses display complex emergent rheological properties that often cannot be predicted from their single-component counterparts. For example, entangled blends of ring and linear polymers have been shown to exhibit enhanced shear thinning and viscosity, as well as prolonged relaxation timescales, compared to pure solutions of rings or linear chains
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Thixotropic constitutive modeling of shear banding by boundary-induced modulus gradient in lamellar gel networks J. Rheol. (IF 3.3) Pub Date : 2022-11-08 Futianyi Wang, Ronald G. Larson
To predict the complex rheology and shear-rate inhomogeneities of lamellar gel networks, we propose a simple thixotropic constitutive model with an elastoplastic stress and a smoothly decreasing modulus near a solid boundary, motivated by the analysis of the effect of confinement and shear flow on lamellae orientation near surfaces. We show that the model qualitatively captures the important features
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Dynamics of annular solvent droplets under capillary thinning of non-entangled polymer solution J. Rheol. (IF 3.3) Pub Date : 2022-11-08 Andrey V. Subbotin, Alexander N. Semenov
Formation and coalescence of solvent droplets on a thread of polymer solution at the final stage of capillary pinching is studied theoretically. It is considered that macromolecules are already almost completely stretched along the extension axis and their contour length exceeds the diameter of the thread. In this regime, the radius of polymer string decreases slowly with time under the action of capillary
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Contactless interfacial rheology: Probing shear at liquid–liquid interfaces without an interfacial geometry via fluorescence microscopy J. Rheol. (IF 3.3) Pub Date : 2022-11-08 Iain Muntz, James A. Richards, Sam Brown, Andrew B. Schofield, Marcel Rey, Job H. J. Thijssen
Interfacial rheology is important for understanding properties such as Pickering emulsion or foam stability. Currently, the response is measured using a probe directly attached to the interface. This can both disturb the interface and is coupled to flow in the bulk phase, limiting its sensitivity. We have developed a contactless interfacial method to perform interfacial shear rheology on liquid/liquid
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Rheology of polydisperse nonspherical graphite particles suspended in mineral oil J. Rheol. (IF 3.3) Pub Date : 2022-11-08 Th. Larsen, A. L. Søbye, J. R. Royer, W. C. K. Poon, T. Larsen, S. J. Andreasen, A. D. Drozdov, J. D. C. Christiansen
We study the role of filler concentration and microphysics on the rheology of polydisperse flake-graphite particles suspended in Newtonian mineral oil. Under steady shear, our samples exhibit shear thinning, and yielding behavior is observed for volume fractions ϕ>0.18. Time-temperature superposition was observed using an Arrhenius-type horizontal shift factor, giving a flow activation energy that
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Phase-field simulations of morphology development in reactive polymer blending J. Rheol. (IF 3.3) Pub Date : 2022-11-07 Rajarshi Sengupta, Mukul D. Tikekar, James V. Raj, Kris T. Delaney, Michael C. Villet, Glenn H. Fredrickson
Reactive blending is an efficient method for synthesizing polymer blends. Industrially, this process is carried out in extruders, where the reacting polymers and the generated copolymer are subjected to high shear stresses. The dynamics of the process, and the resulting morphology is dictated by a coupling of the hydrodynamic forces in the extruder, the thermodynamic interactions between species, and
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Large amplitude oscillatory shear behavior of thermoresponsive hydrogels: Single versus double network J. Rheol. (IF 3.3) Pub Date : 2022-11-07 Sara Tarashi, Hossein Nazockdast, Alireza Bandegi, Saeid Shafaghsorkh, Gholamhossein Sodeifian, Reza Foudazi
Double network (DN) hydrogels have been recognized as new tough materials for several industries due to their precise structural platforms and significant properties. However, a comprehensive understanding of microstructural changes of DN hydrogels under large deformations is required to extend their applications. In this work, we use the large amplitude oscillatory shear (LAOS) technique to study
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How double dynamics affects the large deformation and fracture behaviors of soft materials J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Kunpeng Cui, Jian Ping Gong
Numerous mechanically strong and tough soft materials comprising of polymer networks have been developed over the last two decades, motivated by new high-tech applications in engineering and bio-related fields. These materials are characterized by their dynamic complexities and large deformation behaviors. In this Review, we focus on how chain dynamics affects the large deformation and fracture behaviors
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Linear viscoelasticity of double associative polymers with varied density of the secondary interaction J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Huanhuan Yang, Shilong Wu, Quan Chen
This study examines the linear viscoelasticity of double-associative ionomers based on poly(hexyl methacrylate). The ionomer samples are unentangled and contain a fixed number of ionic stickers per chain, fion≅4, but a varied number of hydrogen-bonding stickers per chain, fH = 5.5–27. Increasing fH has distinct effects on the glassy and rubbery dynamics. On the one hand, the glassy relaxation mode
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Rheology and self-healing of amine functionalized polyolefins J. Rheol. (IF 3.3) Pub Date : 2022-11-01 B. M. Yavitt, T. Tomkovic, D. J. Gilmour, Z. Zhang, N. Kuanr, E. van Ruymbeke, L. L. Schafer, S. G. Hatzikiriakos
The rheological and self-healing behavior of a class of catalytically synthesized amine-functionalized polyolefins is investigated. We demonstrate that these materials possess tunable rheological properties according to the molecular weight and display autonomous self-healing. The linear viscoelastic properties are modeled using a tube-based model developed by Hawke et al. [J. Rheol., 60, 297–310,
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Rheological investigation on the associative properties of poly(vinyl alcohol) solutions J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Daniele Parisi, Colin D. Ditillo, Aijie Han, Seth Lindberg, Mark W. Hamersky, Ralph H. Colby
We report intrinsic viscosity and flow curve measurements on a set of five industrial poly(vinyl alcohol) (PVOH) samples, with varying degree of hydrolysis, molecular weight, and concentration in two solvents: water and dimethyl sulfoxide (DMSO). Aqueous poly(vinyl alcohol) solutions exhibit clear features of associative polymers, and the hydroxyl-carbonyl hydrogen bonds seem to dominate polymer chain
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Mechanical switching of a comblike dual dynamic polymer network J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Paola Nicolella, Sebastian Seiffert
Hydrogels are polymer networks swollen in water and, therefore, suitable for biomedical applications. For this purpose, hydrogels have to mimic the functionality and mechanics of natural tissues. In drug delivery, for example, the diffusion is crucial and can be controlled through targeted variation of the network mesh-size. In tissue engineering, on the other side, the mechanics plays a fundamental
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Microrheological study of single chain dynamics in semidilute entangled flexible polymer solutions: Crossover from Rouse to Zimm modes J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Tsutomu Indei, Tetsuharu Narita
The dynamics of polymer chains in entangled semidilute solution have been of theoretical and experimental interest. Among a number of characteristic lengths and times of the polymer in solution, those of the correlation blob are the key to understand the applicability of the Rouse and Zimm models to rheology of the semidilute solution. Direct rheological measurements of Rouse and Zimm modes are limited
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A single-chain model for the linear viscoelasticity of unentangled melts of associating polymers J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Hongwei Liu, Giovanni Ianniruberto, Giuseppe Marrucci
Existing single-chain models for unentangled associating polymers account for the association by assigning the sticky junctions a large value of the monomeric friction coefficient, which prevents them from moving in space unless stickers effectively dissociate. With such an assumption, comparison of model predictions with linear viscoelastic data is not fully successful in the intermediate range of
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Relaxation dynamics of supramolecular polymer networks with mixed cross-linkers J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Donghua Xu, Bradley D. Olsen, Stephen L. Craig
The linear rheological properties of supramolecular polymer networks formed by mixtures of two different bis-Pd(II) cross-linkers with poly(4-vinylpyridine) in dimethyl sulfoxide are examined. The changes in storage and loss moduli of the networks with mixed cross-linkers are compared to those of samples with a single type of cross-linkers. While the plateau moduli, and presumably network topology
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Dynamics of entangled metallosupramolecular polymer networks combining stickers with different lifetimes J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Yanzhao Li, Christina Pyromali, Flanco Zhuge, Charles-André Fustin, Jean-François Gohy, Dimitris Vlassopoulos, Evelyne van Ruymbeke
We study the linear viscoelastic properties of polymeric networks formed by poly(n-butyl acrylate) telechelic stars end-capped with 2,2:6,2″-terpyridine (Star-PnBA-tpy4) and two types of metal-ligand cross-links with different lifetimes. The influence of interactions, mediated by temperature, nature of metal ions, and ion content, on the linear viscoelastic behavior of both single and double dynamics
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Nonlinear shear rheology of single and double dynamics metal-ligand networks J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Christina Pyromali, Yanzhao Li, Flanco Zhuge, Charles-André Fustin, Evelyne van Ruymbeke, Dimitris Vlassopoulos
We present a systematic experimental study of the shear rheology of metallosupramolecular assemblies based on entangled telechelic star polymers comprising one (single dynamic network) or two (double dynamics network) types of physical bonds with the aim to unravel the role of concentration and strength of these bonds on the nonlinear response. Model dynamic networks functionalized with terpyridine
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Tailoring the linear viscoelastic response of industrial double dynamics networks through the interplay of associations J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Consiglia Carillo, Stephan Zoellner, Evelyne van Ruymbeke, Dimitris Vlassopoulos
We investigate the linear viscoelastic properties of industrial pressure sensitive adhesives comprising double networks with an entangled acrylate-based polymer and two types of intermolecular associations (crosslinking), permanent (epoxide) and reversible (metal-chelate), having different compositions. A combination of shear rheometry and an appropriately modified version of the Time Marching Algorithm
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Fracture of dual crosslink gels with permanent and transient crosslinks: Effect of the relaxation time of the transient crosslinks J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Jingwen Zhao, Louis Debertrand, Tetsuharu Narita, Costantino Creton
We investigate the fracture properties of poly(acrylamide-co-1-vinylimidazole) dual crosslink hydrogels [P(AAm-co-VIm)-M2+ gels] containing a small fraction of covalent bonds and a majority of dynamic bonds based on metal coordination bonds (Ni2+ or Zn2+). Unlike a previous study on a different dual crosslink hydrogel system having slower dynamic bonds based on poly(vinylalcohol) and borate ions (PVA-Borax
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Multispeckle diffusing wave spectroscopy as a tool to study heterogeneous mechanical behavior in soft solids J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Jianzhu Ju, Luca Cipelletti, Stephan Zoellner, Tetsuharu Narita, Costantino Creton
Multiple speckle diffusing wave spectroscopy (MSDWS) can be applied to measure spatially heterogeneous mechanical behavior in soft solids, with high sensitivity to deformation and both spatial and temporal resolution. In this paper, we discuss the mathematical approach behind the quantification of the deformation rate from MSDWS data and provide guidelines for optimizing the selection of experimental
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Time-resolved microstructural changes in large amplitude oscillatory shear of model single and double component soft gels J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Gavin J. Donley, Minaspi Bantawa, Emanuela Del Gado
Soft particulate gels can reversibly yield when sufficient deformation is applied, and the characteristics of this transition can be enhanced or limited by designing hybrid hydrogel composites. While the microscopic dynamics and macroscopic rheology of these systems have been studied separately in detail, the development of direct connections between the two has been difficult, particularly with regard
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Exploiting the lower disorder-to-order temperature in polystyrene-b-poly(n-butyl acrylate)-b-polystyrene triblock copolymers to increase their flow resistance at high temperature J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Clément Coutouly, Evelyne van Ruymbeke, Laurence Ramos, Philippe Dieudonné-George, Charles-André Fustin
This work focuses on the temperature-dependent structural and rheological characterization of polystyrene-b-poly(n-butyl acrylate)-b-polystyrene triblock copolymers (PS-b-PnBA-b-PS) in the melt and, in particular, on their ability to show a lower disorder-to-order temperature (LDOT). To this aim, copolymers of varying block lengths, but keeping the PnBA block as a major component, were synthesized
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Molecular weight effects on the stress-relaxation behavior of soft thermoplastic elastomer by means of temperature scanning stress relaxation (TSSR) J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Simone Sbrescia, Tom Engels, Evelyne Van Ruymbeke, Michelle Seitz
The mechanical properties of multiblock copolymer thermoplastic elastomers (TPEs) are governed by the interplay of different reversible dynamics [e.g., hard block (HB) association and chain entanglements]. Understanding how these physical processes influence the high-temperature deformation behavior is relevant as many TPEs lose toughness with increasing temperature. Increasing molecular weight (Mw)
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Dynamics of dual-junction-functionality associative polymer networks with ion and nanoparticle metal-coordinate cross-link junctions J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Jake Song, Qiaochu Li, Pangkuan Chen, Bavand Keshavarz, Brian S. Chapman, Joseph B. Tracy, Gareth H. McKinley, Niels Holten-Andersen
We provide a canonical introduction to dual-junction-functionality associative polymer networks, which combine high and low functionality (f) dynamic cross-link junctions to impart load-bearing, dissipation, and self-repairing ability to the network. This unique type of network configuration offers an alternative to traditional dual-junction networks consisting of covalent and reversible cross-links
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Equilibration dynamics of a dynamic covalent network diluted in a metallosupramolecular polymer matrix J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Rowanne Lyons, Larissa Hammer, Alexis André, Charles-André Fustin, Renaud Nicolaÿ, Evelyne van Ruymbeke
We investigate the viscoelastic properties of double dynamic networks (DDNs) based on side-functionalized PnBA chains. One of these networks is highly crosslinked by metal-ligand junctions characterized by a fast association/dissociation dynamics, while the other network is sparsely crosslinked with slow dynamic covalent networks (DCNs). We first show that modulating the dynamics of the metallosupramolecular
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Butyl rubber as a macro-cross-linker in the preparation of a shape-memory and self-healing polymer J. Rheol. (IF 3.3) Pub Date : 2022-11-01 Burak Tavsanli, Cigdem Bilici, Pelin Sungur, Semra Ide, Oguz Okay
Recently, a simple strategy was developed for preparing interconnected interpenetrating polymer networks (IPNs) based on butyl rubber (IIR) and poly(n-octadecyl acrylate) (PC18A). Solvent-free UV polymerization of n-octadecyl acrylate (C18A) monomer in the melt of IIR at ambient temperature resulted in IPNs with self-healing and shape-memory functions. Here, we demonstrate that the use of IIR grafted
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Ordered domains in sheared dense suspensions: The link to viscosity and the disruptive effect of friction J. Rheol. (IF 3.3) Pub Date : 2022-08-31 Abhay Goyal, Emanuela Del Gado, Scott Z. Jones, Nicos S. Martys
Monodisperse suspensions of Brownian colloidal spheres crystallize at high densities, and ordering under shear has been observed at densities below the crystallization threshold. We perform large-scale simulations of a model suspension containing over 105 particles to quantitatively study the ordering under shear and to investigate its link to the rheological properties of the suspension. We find that
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Low-frequency elastic plateau in linear viscoelasticity of polyelectrolyte coacervates J. Rheol. (IF 3.3) Pub Date : 2022-08-31 Huiling Li, Ying Liu, Abhishek Shetty, Ronald G. Larson
A thorough study is made of the dependences on salt concentration and polymer chain lengths of the low-frequency plateau of coacervates of poly (diallyl dimethyl ammonium chloride), PDADMAC, and poly (sodium 4-styrenesulfonate), PSS. The reliability and reproducibility of these measurements are carefully checked by determining the frequency-dependent stress limits of the rheometer through the use of
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Determination of the molecular weight distribution of ultrahigh molecular weight polyethylene from solution rheology J. Rheol. (IF 3.3) Pub Date : 2022-09-01 Vincenzo Ianniello, Salvatore Costanzo, Rossana Pasquino, Giovanni Ianniruberto, Enrico Troisi, Theo A. Tervoort, Nino Grizzuti
We investigate the linear rheology of ultrahigh molecular weight polyethylene (UHMWPE) solutions with the aim of determining the molecular weight distribution of the polymer. The UHMWPE is dissolved in oligo-ethylene in order to avoid issues related to unfavorable interactions with the solvent. To prepare the solutions, UHMWPE, solvent, and a fixed amount of antioxidants are mixed by means of a corotating
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The Mnemosyne number and the rheology of remembrance J. Rheol. (IF 3.3) Pub Date : 2022-08-29 Safa Jamali, Gareth H. McKinley
The concept of a Deborah number is widely used in the study of viscoelastic materials to represent the ratio of a material relaxation time to the time scale of observation and to demarcate transitions between predominantly viscous or elastic material responses. However, this construct does not help quantify the importance of long transients and nonmonotonic stress jumps that are often observed in more
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Thixotropic spectra and Ashby-style charts for thixotropy J. Rheol. (IF 3.3) Pub Date : 2022-08-29 Samya Sen, Randy H. Ewoldt
There is no universal model for thixotropy, and comparing thixotropic effects between different fluids is a subtle yet challenging problem. We introduce a generalized (model-insensitive) framework for comparing thixotropic properties based on thixotropic spectra. A superposition of exponential stress modes distributed over thixotropic time scales is used to quantify buildup and breakdown times and