Article
Polymer Science
Fan Wang, Lu-Kun Feng, Ye-Di Li, Hong-Xia Guo
Summary: Dissipative particle dynamics (DPD) is a promising method for studying entangled polymers, but its applicability as a model for ideal chains and accurate description of entangled melts is not well understood. In this study, we comprehensively investigate the structure, dynamics, and linear viscoelasticity of a DPD entangled model system, specifically a semiflexible linear polymer melt. Our results show that the DPD model accurately predicts the monomer motion and relaxation behavior of entangled polymers, following the predictions of reptation theory. However, there are some limitations to the reptation theory, as evidenced by anomalous sub-diffusive motion and cross-correlation between chains. Overall, the semiflexible linear DPD model is able to capture the static and dynamic properties of entangled polymer melts.
CHINESE JOURNAL OF POLYMER SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Zhenghao Wu, Andreas Kalogirou, Antonio De Nicola, Giuseppe Milano, Florian Mueller-Plathe
Summary: In this study, a multi-chain slip-spring model was introduced into hybrid particle-field simulations to mimic the entangled dynamics of polymer melts. The results showed that at long timescales, dynamical properties were in good agreement with traditional molecular dynamics simulations and theoretical predictions.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2021)
Article
Polymer Science
Mahdi Boudaghi, Brian J. J. Edwards, Bamin Khomami
Summary: The temporal and spatial evolution of shear banding in polyethylene solutions was studied during startup and steady-state shear flow. A high-fidelity method was developed to simulate and evaluate this phenomenon. The study observed transient shear banding during startup flow, with inhomogeneous concentration distribution within the system.
Article
Polymer Science
Jurek Schneider, Frank Fleck, Hossein Ali Karimi-Varzaneh, Florian Mueller-Plathe
Summary: Using dissipative-particle-dynamics simulations, we studied elastomeric networks and found that slip springs can restore the topological effects of network strands. Uniaxial strain experiments revealed that the contributions of cross-links and entanglements to the shear modulus in a slip-spring model network are consistent with those reported for comparable hard-core Kremer-Grest networks.
Article
Physics, Multidisciplinary
Michael C. Burroughs, Yuanyi Zhang, Abhishek M. Shetty, Christopher M. Bates, L. Gary Leal, Matthew E. Helgeson
Summary: This study experimentally confirmed the concentration profile of entangled polymer solutions under shear, demonstrating the critical importance of flow-concentration coupling in such systems. The findings showed that at shear rates above a critical value, concentration and velocity profiles can develop bands, consistent with model predictions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Mechanics
Takeshi Sato, Ronald G. Larson
Summary: In this study, a micelle-slip-spring model incorporating breakage and rejoining events and stress-induced micelle breakage is used to investigate the linear and nonlinear shear and extensional rheological properties. The model shows good agreement with experimental data for the start-up of the shearing flow, but lacks data for extensional flow testing. The transient and steady shear properties predicted by the model fit well with the Giesekus model, while the extensional rheological properties are poorly predicted by both the Giesekus and the PTT models. A constitutive model that accurately captures the behavior of the slip-spring model in shear and extensional flows is needed for future work.
JOURNAL OF RHEOLOGY
(2022)
Article
Polymer Science
Yexin Zheng, Mesfin Tsige, Shi-Qing Wang
Summary: In this study, molecular dynamics simulations were used to investigate the entanglement lockup phenomena in the uniaxial melt stretching of entangled polymer melts. The results revealed that under high strains, the entanglement network became increasingly tighter, leading to chain tension and the formation of network junctions. It was hypothesized that the interchain entanglement at junctions can lockup as long as certain conditions are met. This study provides insights into the mechanical properties of polymer materials.
MACROMOLECULAR RAPID COMMUNICATIONS
(2023)
Article
Engineering, Marine
Xinru Du, Hidemi Mutsuda, Yuya Wasada, Takuji Nakashima
Summary: Frictional drag reduction (DR) can save fuel in marine vehicle propulsion. This study introduces a novel numerical model that combines mesoscopic method with computational fluid dynamics (CFD) techniques, and validates the model using direct numerical simulation (DNS) and large eddy simulation (LES) methods. The model investigates the influence of polymer region height on non-uniform polymer DR and reveals significant DR efficiency even when the polymer region does not extend across the entire fluid area. This model lays the foundation for further research on polymer coatings DR and energy conservation of vessels.
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
Thermodynamics
Marzie Borhani, Somaye Yaghoubi
Summary: In this study, dissipative particle dynamics with energy conservation (eDPD) was used to simulate the hydrodynamic behavior and heat transfer of DPD particles in a two-dimensional channel. The results showed successful simulation of indented geometry by using four frozen layers for modeling walls, leading to improved accuracy. Additionally, factors such as wall alignment, initial particle arrangement, cell size for averaging, and time steps in output results were investigated.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Polymer Science
Yanbin Ma, Xiaoqin Yuan, Ruifeng Jiang, Jianhe Liao, Rentong Yu, Yongping Chen, Lusheng Liao
Summary: In this study, molecular dynamics simulation and dissipative particle dynamics simulation were used to predict the compatibility between natural rubber (NR) and chloroprene rubber (CR) based on Flory-Huggins parameters. The simulation results were verified by Fourier transform infrared spectroscopy and dynamic mechanical analysis. It was found that the compatibility between NR and CR was poor, but it could be improved when the CR content was 50% or 90%. Phase separation in the form of spinodal decomposition with a critical temperature of 390 K was observed according to the phase diagram. Different microphase structures such as spherical, lamellar, and bicontinuous phases were observed in the blends with varying CR contents through morphology analysis.
Article
Polymer Science
Wei Li, Pritam K. Jana, Alireza F. Behbahani, Georgios Kritikos, Ludwig Schneider, Patrycja Polinska, Craig Burkhart, Vagelis A. Harmandaris, Marcus Mueller, Manolis Doxastakis
Summary: A hierarchical triple-scale simulation methodology is applied to investigate the dynamics of cis-1,4 polyisoprene melts, showing good agreement with experimental data, especially for highly entangled polymer melts. The study provides parameter-free predictions on the dynamics of polymeric materials.
Article
Chemistry, Physical
Yedi Li, Hongxia Guo
Summary: In this study, the slip phenomena and individual dynamics of interfacial copolymer chains in entangled polymer-polymer interfaces are analyzed using simulations. The study reveals two distinct power-law regions of slip velocity against interfacial shear stress under fast shear flow. Furthermore, the study investigates the individual chain dynamics of interfacial copolymers under weak and strong incompatibility conditions.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Multidisciplinary
Anastasiia O. Krushynska, Antonio S. Gliozzi, Alberto Fina, Dmitry Krushinsky, Daniele Battegazzore, Miguel A. Badillo-Avila, Monica Acuautla, Stefano Stassi, Camilla Noe, Nicola M. Pugno, Federico Bosia
Summary: Phononic materials are artificial composites with the ability to control acoustic waves in solids, their performance is determined by structure and mechanical/material properties of constituents. Dynamics of polymer phononic materials with different architectures made of thermoset and thermoplastic polymers are characterized, and the reliability of elastic and viscoelastic material models is evaluated in broad frequency ranges.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Physical
Joseph D. Dietz, Robert S. Hoy
Summary: The widely used double-bridging hybrid method for equilibrating simulated entangled polymer melts loses effectiveness as chain stiffness increases. By combining the double-bridging hybrid method with core-softened pair potentials, the energy barriers can be reduced substantially, allowing for more efficient equilibration of polymer melts with increasing chain stiffness.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Mechanics
Lixin Yang, Takashi Uneyama, Yuichi Masubuchi, Yuya Doi
Summary: The nonlinear shear and elongational rheology of entangled poly(propylene carbonate) melts with different molecular weights and relatively narrow molecular weight distribution were investigated. The results showed that the melts exhibited shear thinning behavior and stress overshoot at high shear rates, while the shear rate dependence of the steadystate viscosity followed the empirical Cox-Merz rule. In uniaxial elongational measurements, the viscosity growth functions deviated slightly from the linear viscoelastic envelope at high Weissenberg number Wi(d), and the steady-state viscosity exhibited elongational thinning. Comparison between poly(propylene carbonate) and polystyrene melts with similar entanglement number showed similar viscosity growth curves, indicating comparable friction reduction due to stretch/orientation.
NIHON REOROJI GAKKAISHI
(2022)
Letter
Mechanics
Yuichi Masubuchi
NIHON REOROJI GAKKAISHI
(2022)
Article
Polymer Science
Yuya Doi, Jinya Kitamura, Takashi Uneyama, Yuichi Masubuchi, Atsushi Takano, Yoshiaki Takahashi, Yushu Matsushita
Summary: In this study, the viscoelastic properties of comb-shaped ring polystyrene samples with different branch chain lengths were examined. The results showed that even samples with the shortest branch chains exhibited intermolecular branch chain entanglement. The effects of different backbone molecular structures on the terminal relaxation behavior were discussed.
Review
Mechanics
Yuichi Masubuchi
Summary: This report reviews the 49th volume published last year (2021). The statistics indicate that the total number of published papers and the ratio of English manuscripts are 37 and 0.57, respectively, which are similar to the average of previous volumes. The contents cover various fields of rheology, but the distribution is uneven and differs from what is observed in meetings.
NIHON REOROJI GAKKAISHI
(2022)
Article
Mechanics
Yuichi Masubuchi, Lixin Yang, Takashi Uneyama, Yuya Doi
Summary: In this study, the effect of chemistry-dependent friction on the shear rheology of polymers was investigated using primitive chain network simulations. The simulation results showed that varying friction according to segment orientation improved the agreement with experimental data, particularly for the shear rate dependence of the stress overshoot under high shear.
NIHON REOROJI GAKKAISHI
(2022)
Article
Mechanics
Takashi Uneyama, Tatsuma Oishi, Takato Ishida, Yuya Doi, Yuichi Masubuchi
Summary: In this paper, the stress tensor of a rigid dumbbell is derived using the virtual work method. The dynamic equations are rewritten to be consistent with the rigid constraint, and a virtual deformation is applied to the dumbbell. The stress tensor and dynamic equation for the overdamped dumbbell are obtained and shown to reproduce the Green-Kubo type linear response formula.
NIHON REOROJI GAKKAISHI
(2022)
Article
Mechanics
Manfred H. Wagner, Esmaeil Narimissa, Yuichi Masubuchi
Summary: In fast elongational flows, the viscosity of linear polymer melts decreases with increasing strain rate, even beyond the contraction rate of the polymer. Two possible explanations for this phenomenon are the reduction of monomeric friction and the reduction of tube diameter with increasing deformation.
Article
Mechanics
Daniele Parisi, Emmanouil Vereroudakis, Yuichi Masubuchi, Giovanni Ianniruberto, Giuseppe Marrucci, Dimitris Vlassopoulos
Summary: Evidence from state-of-the-art experiments, modeling and simulations suggests the existence of an undershoot in fast flows of entangled polymers, following the overshoot during shear startup. Blending two entangled homopolymers at different compositions affects the undershoot, possibly by changing the distribution of relaxation times. By modifying the tube-based model and using simulations, we demonstrate how the undershoot depends on the blend composition.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2023)
Article
Mechanics
Yuichi Masubuchi, Giovanni Ianniruberto, Manfred Wagner, Giuseppe Marrucci
Summary: The description of elongational rheology of concentrated polymers suggests that the friction coefficient decreases in fast flows compared to its equilibrium value. However, the proposed models still uphold the fluctuation-dissipation theorem (FDT) even when out of equilibrium. Recent analysis of unentangled polystyrene (PS) melts indicates that FDT is violated in fast flows, where the Brownian force intensity remains independent despite the decrease in friction coefficient. Other molecular dynamics simulations of PS oligomers show a different violation of FDT, where the diffusion coefficient grows more than the inverse of the friction coefficient. Brownian simulations using a multi-chain slip-link model were conducted in this study to examine two different friction reduction models for entangled PS melts. The results support models that retain FDT as its violation does not significantly affect predictions of nonlinear rheology.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2023)
Article
Polymer Science
Yuichi Masubuchi, Yuya Doi, Takato Ishida, Naoyuki Sakumichi, Takamasa Sakai, Koichi Mayumi, Takashi Uneyama
Summary: The influence of branch functionality on the mechanical properties of polymer networks is not yet fully understood. In a recent study, Fujiyabu et al. demonstrated that polymer networks made from tri-branch prepolymers exhibit superior mechanical properties compared to tetra-branch analogues. However, the underlying mechanism is still unclear. In this study, coarse-grained molecular simulations were performed to investigate the effect of branch functionality on mechanical properties. The results suggest that the mechanical superiority of tri-branch networks is due to a fundamental structural difference generated during gelation.
Article
Mechanics
Yuichi Masubuchi
Summary: In the tube model framework, the survival fraction of dilated tube, phi '(t), plays a crucial role in describing the relaxation of the entire system. This study explores various structural quantities as potential candidates for defining phi '(t) in multi-chain simulations. The results suggest that n(s)(t)/n(t) is comparable to phi '(t).
NIHON REOROJI GAKKAISHI
(2023)
Article
Polymer Science
Yuichi Masubuchi, Yuya Doi, Takato Ishida, Naoyuki Sakumichi, Takamasa Sakai, Koichi Mayumi, Kotaro Satoh, Takashi Uneyama
Summary: The influence of node functionality on polymer network fracture is investigated in this study. It is found that networks with a node functionality of 3 exhibit superior fracture properties at high conversion ratios. Furthermore, the fracture characteristics are found to be related to cycle rank and broken strand fraction.
Article
Physics, Fluids & Plasmas
Fumiaki Nakai, Martin Kroger, Takato Ishida, Takashi Uneyama, Yuya Doi, Yuichi Masubuchi
Summary: It has been observed that rod-shaped particles embedded in certain matrices can exhibit an increase in their diffusivity when the matrix density is increased, similar to the behavior of tube models. However, a study using a kinetic Monte Carlo scheme shows that even in a system without kinetic constraints, the diffusivity of rod-like particles still increases when their aspect ratio exceeds a certain threshold. This suggests that the kinetic constraint is not a necessary condition for the increase in diffusivity.
Article
Physics, Fluids & Plasmas
Fumiaki Nakai, Yuichi Masubuchi, Yuya Doi, Takato Ishida, Takashi Uneyama
Summary: Diffusivity in certain soft matter and biological systems, referred to as fluctuating diffusivity, can change over time. This study introduces a novel explanation for fluctuating diffusivity through stochastic simulations of binary gas mixtures. When one component's concentration is significantly small and its mass differs from the major component, the minor component displays fluctuating diffusivity when its mass is considerably smaller. The cause of this fluctuating diffusivity is attributed to the separation of time scales between the relaxation of velocity direction and the speed of the minor component molecule.
Article
Chemistry, Multidisciplinary
Teerat Watcharatpong, Taweesak Pila, Thana Maihom, Tomohiro Ogawa, Takuya Kurihara, Koji Ohara, Tadashi Inoue, Hiroyasu Tabe, Yong-Sheng Wei, Kanokwan Kongpatpanich, Satoshi Horike
Summary: The melt state structure of a one-dimensional coordination polymer crystal has been characterized using various techniques. It was found that a coordination polymer-forming liquid is formed above its melting temperature, with the coordination bonds preserved. The presence of variable chain configurations and moderate cohesive interactions in adjacent chains is crucial for this rarely observed phenomenon. The structure of the melt is similar to common one-dimensional organic polymer melts.
