Article
Materials Science, Composites
Liming Wang, Miao Du, Guorong Shan, Qing Lu, Min Zuo, Yihu Song, Qiang Zheng
Summary: This paper investigates the nonlinear viscoelastic behavior of rubber composites. The study finds that frequency sweep tests provide more information about viscoelastic response, and time-temperature superposition is applicable to nonlinear viscoelastic behavior. The behavior of filled vulcanizates is similar to that of unfilled vulcanizates, indicating the same response mechanism.
COMPOSITES SCIENCE AND TECHNOLOGY
(2022)
Article
Chemistry, Physical
Silabrata Pahari, Bhavana Bhadriraju, Mustafa Akbulut, Joseph Sang-Il Kwon
Summary: This study extends the rheology modeling of polymers to wormlike micelles (WLMs) and successfully predicts linear rheology and characteristic relaxation times. The findings show that reptation leads to a continuous increase in viscosity, while union-scission contributes to a decrease in viscosity of WLM solutions under higher salinity and pH conditions.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Polymer Science
Daniele Parisi, Salvatore Costanzo, Youncheol Jeong, Junyoung Ahn, Taihyun Chang, Dimitris Vlassopoulos, Jonathan D. Halverson, Kurt Kremer, Ting Ge, Michael Rubinstein, Gary S. Grest, Watee Srinin, Alexander Y. Grosberg
Summary: Experimental, simulation, and theoretical studies on the steady-state shear viscosity of unconcatenated ring polymer melts show weaker shear thinning compared to linear polymers, with a power law relationship between shear viscosity and shear rate independent of chain length.
Article
Polymer Science
Xiangxi Meng, Yifeng Du, Yalin Liu, E. Bryan Coughlin, Sarah L. Perry, Jessica D. Schiffman
Summary: This study demonstrates for the first time that linear, nonentangled oligomeric polyelectrolytes can be electrospun into fibers. By using the complex coacervation phenomenon, the electrospinning efficiency was significantly improved compared to traditional studies investigating polymer solution parameters.
Article
Energy & Fuels
Hao Wu, Jijiang Ge, Liu Yang, Tianci Zhang, Mingjia Liu, Hongbin Guo
Summary: The article investigates the relationship between various mechanical properties and concentration of PAM gels, revealing that concentration has a significant impact on the plateau modulus, degree of stiffening, and fracture strain. The plateau modulus of unentangled gels is controlled by crosslinking density, while entangled gels display a power law relationship with polymer concentration. Increasing crosslinker concentration or decreasing polymer concentration enhances the degree of stiffening and reduces fracture strain. Furthermore, the contribution of gellant concentration to the fracture stress of gels is weakened as the polymer concentration exceeds the entanglement concentration.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Physics, Fluids & Plasmas
Kenji Nishizawa, Natsuki Honda, Shono Inokuchi, Hiroyuki Ebata, Takayuki Ariga, Daisuke Mizuno
Summary: In this study, the fluctuating dynamics of colloidal particles in weakly crosslinked F-actin networks were investigated using optical-trap-based microrheology. The statistics of jump dynamics were analyzed, revealing how heterogeneous relaxations observed in equilibrium systems became homogeneous under constant forcing beyond the linear regime.
Article
Mechanics
Takeshi Sato, Youngdon Kwon, Yumi Matsumiya, Hiroshi Watanabe
Summary: In this work, a constitutive equation for the Rouse model was derived taking into account changes in the spring constant, bead friction coefficient, and Brownian force intensity under flow. The equation has a functional form and a memory function depending on the parameters defined under flow conditions. It serves as a basis for analyzing nonlinear rheological behavior and reproduces previous theoretical results under specific conditions.
Article
Engineering, Mechanical
Raju Ahamed, Ian Howard, Kristoffer McKee
Summary: This paper investigates the dynamics of a single-degree-of-freedom magnetic spring-based oscillator system. The system consists of a nonmagnetic shaft, a floating permanent magnet, and two fixed permanent magnets that repel each other. The magnetic properties and restoring force of the system are studied, and the analytical investigation is validated through experimental and numerical analyses. The linear and nonlinear coefficients are analyzed based on the magnetic restoring force, and the effects of gravitational force on the equilibrium position are examined. The system dynamics, including damping ratio, eigenvalues, and natural frequencies, are investigated with and without electromechanical coupling. The energy generation capacity of the system is also examined using electromechanical coupling.
NONLINEAR DYNAMICS
(2023)
Article
Engineering, Chemical
Milad Kamkar, Mohsen Janmaleki, Elnaz Erfanian, Amir Sanati-Nezhad, Uttandaraman Sundararaj
Summary: Gelatin-based hydrogels are widely used in biomedical applications, but their mechanical behavior under large deformations is not well understood. In this study, a novel technique was used to evaluate the mechanical response of GelMA hydrogels under large deformations, revealing nonlinear viscoelastic behavior. The concentration of the hydrogel precursor was found to affect the viscoelastic parameters.
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2022)
Article
Engineering, Biomedical
Farkhad Maksudov, Olga Kononova, Aida Llauro, Alvaro Ortega-Esteban, Trevor Douglas, Gabriela N. Condezo, Carmen San Martin, Kenneth A. Marx, Gijs J. L. Wuite, Wouter H. Roos, Pedro J. de Pablo, Valeri Barsegov
Summary: The Fluctuating Nonlinear Spring (FNS) model helps quantify the elasticity and strength of biological particles, predicting their free energy changes and accurately describing their mechanical properties. By applying the FNS theory to bacteriophage P22, Human Adenovirus, and Herpes Simplex virus, it is evident that these nanoshells exhibit low toughness, increased strength with size, and soft modulus.
ACTA BIOMATERIALIA
(2021)
Article
Computer Science, Interdisciplinary Applications
Jeffrey G. Ethier, Andres Cordoba, Jay D. Schieber
Summary: Prior studies have demonstrated the accuracy of the discrete slip-link model (DSM) in predicting the rheology of entangled polymer systems. This work discusses the implementation of the fixed slip-link model and the clustered fixed slip-link model in Python, showing that Python can also utilize GPUs for fast quantitative rheological predictions. The developed pyDSM code allows for easy-to-use GPU computing and can be integrated with other simulation or data analysis software. Evaluation: 8/10
COMPUTER PHYSICS COMMUNICATIONS
(2023)
Article
Mechanics
Jinying Zou, Xiaorong Wang
Summary: Under large amplitude oscillatory shears, an anomalous nonlinear behavior was observed, with the system exhibiting a previously unrecognized concentration transition. This transition results in stress responses maintaining sinusoidal waveforms at any given strain, displaying anomalous nonlinearity. The degree of entanglement in the matrix plays a key role in this unusual rheological event, with higher polymer molecular weight enhancing the transition.
JOURNAL OF RHEOLOGY
(2021)
Article
Chemistry, Physical
Hao Wu, Jijiang Ge, Liu Yang, Tianci Zhang, Hongbin Guo, Longjie Li
Summary: This study investigates the impact of entanglement on the mechanical properties of partially hydrolyzed polyacrylamide gels. In entangled gels, a power law with an exponent of 2.3 dominates the relationship between the plateau modulus and polymer concentration. Conversely, the exponent of the power law is determined by the crosslinking density in unentangled gels. Using an in-situ gelling method, the strain hardening behavior of partially hydrolyzed polyacrylamide gels was observed. It was found that the strain hardening behavior is controllable by the gel component but insensitive to frequency. Gels with higher polymer concentration generally exhibit weaker stiffening tendencies and tend to fracture at lower strain. However, the concentration dependence of non-linear rheology and fracture properties is discontinuous around the entanglement concentration. This can be attributed to the conversion of crosslinking type, from inter-crosslinking to intra-crosslinking, promoted by entanglements. As a result, the fracture stress significantly decreases when the polymer concentration exceeds the entanglement concentration. This article highlights the importance of entanglements in the fracture toughness of polymer gels and provides suggestions for further studies.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Mechanics
Sara Malvar, Francisco Ricardo Cunha
Summary: In this work, a nonlinear phenomenological model for neutrally buoyant force-free active suspension of nematodes is proposed and tested. Limited studies were found on the nonlinear viscoelastic response of the active suspension. The stress is decomposed into elastic and viscous stress contributions through Fourier transform, and Lissajous-Bowditch loops are used as rheological fingerprints to examine the behavior of the nonlinear response of the active fluid. The results show time-strain separable nonlinearity, providing a new physically meaningful interpretation.
Article
Engineering, Mechanical
Xiaoyu Yan, Wei Wang, Xiaojun Liu, Guiqin Zhu, Lihong Zhu
Summary: This paper models the behavior of two plates shearing granular third-body using a coupled FEM-DEM method to study the nonlinear phenomena during the process. The study reveals strong nonlinearity in the fluctuations of friction force and dilatancy phenomenon of clearance between two plates, which vary over different external loads, shearing speeds, and elastic moduli. The nonlinear relationships between stress, velocity, and the discreteness of the third-body are further explored.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2021)
Article
Physics, Multidisciplinary
A. Calderon-Alcaraz, J. Munguia-Valadez, S. I. Hernandez, A. Ramirez-Hernandez, E. J. Sambriski, J. A. Moreno-Razo
Summary: Molecular Dynamics simulations were used to investigate a bidimensional thermotropic liquid crystal system, revealing sharp isotropic-smectic transitions and intermediate nematic phases at different pressures. The topology of the phase diagram in 2D differs from 3D, with nematic regions appearing at lower temperatures and slightly lower densities. The structural behavior under strong confinement showed characteristic topological defects depending on anchoring mode and confining geometry.
FRONTIERS IN PHYSICS
(2021)
Article
Biochemistry & Molecular Biology
Sameer Varma, Joseph P. R. O. Orgel, Jay D. Schieber
Summary: The study found that removal of hydroxylation has minimal effect on the macroscopic structure of collagen, but does have some impact on local structure, hydrogen bonding capacity, and electrostatic attraction. Experimental observations show that hydroxylation removal has minimal effect on collagen's D-band length, gap-overlap ratio, monomer width, and monomer length. Interestingly, de-hydroxylation also has a minor effect on the fibril's Young's modulus, with accompanying changes in triple-helix windings.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Polymer Science
Diego Becerra, Andres Cordoba, Jay D. Schieber
Summary: The study using the discrete slip-link model (DSM) reveals nonuniversality in the nonlinear rheology of polymer melts at large strain rates during the inception of shear flow, despite the theory predicting universal behavior for maximum shear stress and strain at maximum stress based on entanglement activity and Kuhn steps. Primitive path stretching is shown to correspond to the transition of strain-rate-free values to values that scale with dimensionless strain rate. Additionally, differences in scaling exponents for melt and solution data suggest variations in steady-state shear stress, with DSM showing agreement with melt data.
Article
Mechanics
Jay D. Schieber, Andres Cordoba
Summary: This study uses straightforward energy and entropy balances to test the thermodynamic consistency of microstructural rheological models, identifying requirements for non-negative entropy production and adherence to the second law of thermodynamics. Several illustrative examples show that models using relaxation functions proportional to the free energy gradient are easier to check for compliance, while models using other types of relaxation functions may violate thermodynamic laws.
Article
Chemistry, Physical
Luis A. Padilla, Andres A. Leon-Islas, Jesse Funkhouser, Julio C. Armas-Perez, Abelardo Ramirez-Hernandez
Summary: This study explores the self-assembly behavior of binary colloidal mixtures, focusing on the effects of composition, temperature, and pressure. Extensive simulations reveal a rich phase behavior, including the formation of hierarchical structures with potential applications. The results are summarized in phase diagrams, providing insights into the dynamics and phase transitions of the mixtures.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
L. A. Padilla, A. Ramirez-Hernandez, J. Quintana-H, A. L. Benavides, J. C. Armas-Perez
Summary: The study introduces a simple method to design interaction potentials able to generate desired geometrical patterns, combining the GSE method with simulation techniques. By exploring a subfamily of square-shoulder + square well potentials, the research found that the GSE method predictions were qualitatively correct at non-zero temperatures and allowed the construction of phase diagrams for this potential family.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Mechanics
Jeffrey G. Ethier, Pouria Nourian, Rafikul Islam, Rajesh Khare, Jay D. Schieber
Summary: The text discusses extracting viscoelastic properties of a complex fluid using single-particle microrheology by embedding a micrometer-sized particle and tracking its motion through the fluid. It introduces a simple correction to the GSE equation to improve accuracy in molecular dynamics simulations. The corrected HSE equation allows for smaller box sizes, significantly reducing computational costs.
JOURNAL OF RHEOLOGY
(2021)
Article
Polymer Science
Cody T. Bezik, Joshua A. Mysona, Ludwig Schneider, Abelardo Ramirez-Hernandez, Marcus Mueller, Juan J. de Pablo
Summary: A new mesophase in binary blends of A-b-(BA')3 miktoarm star block copolymers and A homopolymers has been discovered, consisting of aperiodic discrete domains of A embedded in a continuous matrix of B. Molecular bridging dominates the mechanical behavior of the mesophase, outweighing the influence of microphase segregation. The application of shear leads to a closer structure resembling its speculated discrete nature.
Article
Mechanics
Andres Cordoba, Jay D. Schieber
Summary: A complete error propagation procedure for passive microrheology is demonstrated, incorporating statistical uncertainty in autocorrelations for any time series data and accounting for correlation in bead position data. Neglecting the correlation in the bead position data can lead to underestimation of the error in the mean-squared displacement of the probe bead by a factor of about 20.
Article
Oncology
Marcela Mercado-Montoya, Tatiana Gomez-Bustamante, Enrique Berjano, Steven Mickelsen, James Daniels, Pablo Hernandez-Arango, Jay Schieber, Erik Kulstad
Summary: Proactive esophageal cooling significantly reduces temperatures and damage in the esophagus during high-power short-duration ablation. These findings provide a mechanistic rationale for the high level of safety achieved so far using proactive esophageal cooling and highlight the inadequacy of temperature monitoring alone in avoiding thermal damage to the esophagus.
INTERNATIONAL JOURNAL OF HYPERTHERMIA
(2022)
Article
Polymer Science
Juhae Park, Vikram Thapar, Yeojin Choe, Luis Adrian Padilla Salas, Abelardo Ramirez-Hernandez, Juan J. de Pablo, Su-Mi Hur
Summary: Bottlebrush polymers have attracted attention as promising candidates for applications in photonics, lithography, energy storage, organic optoelectronics, and drug delivery due to their enhanced mechanical strength and rapid self-assembly into large domains. In this study, a coarse-grained model of bottlebrush polymers is proposed, which can reproduce their experimentally observed persistence lengths and chain conformations. The model is used to investigate the morphologies of this class of materials for various chain architectures and grafting densities.
Article
Materials Science, Multidisciplinary
Carlos A. Salinas-Soto, Juan G. Leon-Islas, Margarita Herrera-Alonso, Abelardo Ramirez-Hernandez
Summary: This study investigates the effect of architectural parameters and hydrophobic solute concentration on the morphology of molecular bottlebrushes using numerical simulations. The results demonstrate that a morphological transition from cylinder to sphere occurs as the concentration of hydrophobic solutes increases. The findings provide guidelines for the molecular design of bottlebrushes and their application-specific morphologies.
ACS APPLIED POLYMER MATERIALS
(2022)
Article
Chemistry, Physical
Tae-Yi Kim, Su-Mi Hur, Abelardo Ramirez-Hernandez
Summary: This study investigates the solution self-assembly of symmetric ABCBA linear pentablock polymers in a selective solvent using dissipative particle dynamics. The effects of block sequence, composition, and polymer concentration on the final morphology and polymer conformations are examined. It is found that block sequence influences the self-assembled morphologies and the solvophilic block located in the middle of the macromolecule leads to the formation of physical gels. The results are summarized in morphology diagrams in the composition-concentration parameter space.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Physics, Fluids & Plasmas
Rudi J. A. Steenbakkers, Marat Andreev, Jay D. Schieber
Summary: This study evaluates the thermodynamic consistency of an anisotropic mobile slip-link model for entangled flexible polymers, focusing on the dynamics of entanglements and chain motion, as well as the contribution of confinement potentials to the stress tensor. The model is formulated in the framework of nonequilibrium thermodynamics, demonstrating the cancellation mechanism of stress contributions due to anisotropic confinement potentials in flow, as necessary for model validity and agreement with previous predictions.
Article
Materials Science, Multidisciplinary
Luis A. Padilla, Abelardo Ramirez-Hernandez
Summary: This study investigates the self-assembly of colloidal nanocrystals at a flat interface through extensive computer simulations, revealing rich phase diagrams and various self-assembly structures. The results could guide experimentalists in designing colloidal nanocrystal arrangements for specific applications.
JOURNAL OF PHYSICS-MATERIALS
(2021)