Article
Polymer Science
Takahiro Murashima, Katsumi Hagita, Toshihiro Kawakatsu
Summary: Coarse-grained molecular dynamics simulations were used to analyze blends of multicyclic and linear polymers under biaxial elongational flow. The blends exhibited an overshoot behavior in the normal stress difference, with multicyclic/linear blends showing a steeper overshoot compared to monocyclic/linear blends. The origin of the overshoot was found to be a topological transition mechanism in the multicyclic chains, which resulted in a drastic change in the stress of the rings.
Article
Nanoscience & Nanotechnology
Sol Mi Oh, So Youn Kim
Summary: Controlling the nanoparticle interface is critical in determining the structure and property of polymer nano composites (PNCs). In addition, the processing condition of PNCs, specifically the type of the initial solvent, plays an important role in their properties. The size of nanoparticles (NPs) also affects the microstructures and rheological properties of PNCs.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Juexin Marfai, Ryan J. Mcgorty, Rae M. Robertson-Anderson
Summary: Polymer topology and non-equilibrium materials are important topics in the study of polymeric fluids' rheology. This research investigates composites of circular DNA and dextran that are pushed out-of-equilibrium via enzymatic digestion. Time-resolved rheology measurements reveal discrete state-switching between dissipative and elastic-like states. The results show that bulk state-switching is not dependent on digestion rates but does depend on the DNA fraction. A model is proposed to explain the continuous molecular-level activity that leads to the macroscopic stress of the composites. This platform has potential applications in various material fields.
ADVANCED MATERIALS
(2023)
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
Polymer Science
Zifeng Wang, Robert M. Ziolek, Mesfin Tsige
Summary: The translocation of polymers through pores and channels is extensively studied in biology and nanotechnology. Recent research using molecular simulations reveals the significant role of knot insertion rates in controlling the translocation dynamics of polymers with different topologies. This study provides new insights into polycatenane translocation and highlights the importance of carefully defining the translocation process.
Article
Polymer Science
Mohamed Adel Alzaabi, Juan Manuel Leon, Arne Skauge, Shehadeh Masalmeh
Summary: Polymer flooding as a successful chemical enhanced oil recovery method has attracted much interest in the oil industry, with injectivity of polymer solutions in porous media being a key factor. This study analyzed data from field polymer injectivity tests in a Middle Eastern reservoir under high-temperature high-salinity conditions, finding non-linear pressure response and complex rheological behavior during polymer injection.
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
Mechanics
Chandi Sasmal
Summary: This study investigates the flow characteristics of a solid and smooth sphere moving steadily along the axis of a cylindrical tube filled with wormlike micellar solutions. Two different constitutive models are used to analyze the rheological behavior, showing that unsteady motion downstream of the sphere occurs when the Weissenberg number exceeds a critical value in the two-species model. However, the single-species Giesekus model predicts a steady flow field. The onset of unsteady motion is delayed as the ratio of sphere to tube diameter decreases, showing qualitative similarity with prior experimental results.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Physics, Fluids & Plasmas
Michael Bley, Upayan Baul, Joachim Dzubiella
Summary: During diffusion-influenced, nonequilibrium chain-growth polymerization, scaling laws of macromolecular conformations qualitatively change, with growing polymers exhibiting a surprising self-avoiding behavior due to nonequilibrium monomer density depletion correlations and longer chain relaxation times compared to the polymerization reaction time. These intrinsic nonequilibrium mechanisms are facilitated by fast and persistent reaction-driven diffusion, similar to pseudochemotactic active Brownian particles, and have implications for time-controlled structure formation in polymer processing applications like reactive self-assembly, photocrosslinking, and three-dimensional printing.
Article
Polymer Science
Katsumi Hagita, Takahiro Murashima, Hiroshi Jinnai
Summary: This study investigates the qualitative behavior of large rings embedded in crosslinked polymer networks through coarse-grained molecular dynamics simulation. The results show that the large rings interfere with the network structure and have an impact on the stress-strain curve. The study also confirms that these embedded rings can act as movable crosslinks and reinforce the network.
Article
Engineering, Petroleum
Marat Sagyndikov, Randall Seright, Sarkyt Kudaibergenov, Evgeni Ogay
Summary: This paper confirms the theoretical argument that fractures can dramatically increase polymer injectivity and eliminate polymer mechanical degradation during polymer flood. A novel method was developed to collect samples of back-produced fluids, which is quick, simple, cheap, and reliable.
Article
Mechanics
Yanan Gong, Valeriy Ginzburg, Sylvie Vervoort, Jaap Den Doelder, Ronald G. Larson
Summary: The method efficiently predicts the linear and nonlinear rheology of polydisperse polymers by selecting representative polymer molecules and has been successful in testing.
JOURNAL OF RHEOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Binqiang Xie, Alain P. Tchameni, Mingwang Luo, Jiantai Wen
Summary: A novel thermo-associating copolymer (PGBA) was synthesized and its thermal stability was confirmed, enhancing the rheological stability of bentonite drilling fluid in a wide temperature range. The improvement was attributed to the thermo-sensitive association behavior and adsorption on bentonite particles of PGBA.
Article
Mechanics
Thomas C. O'Connor, Ting Ge, Gary S. Grest
Summary: This study extensively uses molecular simulations to investigate the equilibrium dynamics, entanglement topology, and nonlinear extensional rheology of symmetric ring-linear polymer blends. The topological analysis reveals a critical ring fraction where the composite entanglement network exhibits maximum constraints. The study also identifies an extensional stress overshoot phenomenon in uniaxial elongation flows, and explains its underlying mechanism.
JOURNAL OF RHEOLOGY
(2022)
Article
Polymer Science
Yuya Doi, Atsushi Takano, Yoshiaki Takahashi, Yushu Matsushita
Summary: The study found that dumbbell polymers form a unique network structure with distinctive entanglement characteristics in the system. Dumbbell PS samples with longer central chains exhibit slower terminal relaxation and retain entanglement features in high-concentration DOP solutions.
Article
Chemistry, Physical
Panagiotis G. Mermigkis, Dimitrios G. Tsalikis, Vlasis G. Mavrantzas
JOURNAL OF CHEMICAL PHYSICS
(2015)
Article
Polymer Science
Panagiotis V. Alatas, Dimitrios G. Tsalikis, Vlasis G. Mavrantzas
MACROMOLECULAR THEORY AND SIMULATIONS
(2017)
Article
Polymer Science
Dimitrios G. Tsalikis, Vlasis G. Mavrantzas, Dimitris Vlassopoulos
Article
Polymer Science
George D. Papadopoulos, Dimitrios G. Tsalikis, Vlasis G. Mavrantzas
Article
Polymer Science
Dimitrios G. Tsalikis, Thanasis Koukoulas, Vlasis G. Mavrantzas, Rossana Pasquino, Dimitris Vlassopoulos, Wim Pyckhout-Hintzen, Andreas Wischnewski, Michael Monkenbusch, Dieter Richter
Article
Polymer Science
Dimitrios G. Tsalikis, Panagiotis V. Alatas, Loukas D. Peristeras, Vlasis G. Mavrantzas
Article
Polymer Science
Dimitrios G. Tsalikis, Vlasis G. Mavrantzas
Article
Chemistry, Physical
Stavros D. Peroukidis, Dimitrios G. Tsalikis, Massimo G. Noro, Ian P. Stott, Vlasis G. Mavrantzas
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2020)
Article
Polymer Science
Dimitrios G. Tsalikis, Terpsichori S. Alexiou, Panagiotis Alatas, Vlasis G. Mavrantzas
MACROMOLECULAR THEORY AND SIMULATIONS
(2020)
Article
Polymer Science
Anna F. Katsarou, Alexandros J. Tsamopoulos, Dimitrios G. Tsalikis, Vlasis G. Mavrantzas
Article
Polymer Science
Terpsichori S. Alexiou, Panagiotis Alatas, Dimitrios G. Tsalikis, Vlasis G. Mavrantzas
Article
Polymer Science
Emmanuel N. Skountzos, Dimitrios G. Tsalikis, Pavlos S. Stephanou, Vlasis G. Mavrantzas
Summary: Molecular dynamics simulations and Rouse theory were used to study the local structure and dynamics of polymer nanocomposite melts. It was found that polymer segments adsorbed on the silica surface exhibit mobility and different terminal groups of PEG chains lead to varied structural and dynamic properties of the nanocomposite melts. The simulations were in excellent agreement with experimental data for the dynamic structure factor, showing the validity of the model in describing the system.
Article
Mechanics
Dimitrios G. Tsalikis, Vlasis G. Mavrantzas, Sotiris E. Pratsinis
Summary: The mechanics and dynamics of molecular collisions in air were investigated using atomistic molecular dynamics simulations. The study found that due to the rotational motion and non-spherical shape of molecules, complex trajectories and multi-molecular collisions occur. By filtering out spurious collisions, the average free path of air was determined to be 38.5 +/- 1nm, which is 43% smaller than the widely accepted value.
Proceedings Paper
Materials Science, Multidisciplinary
Pavlos S. Stephanou, Dimitrios G. Tsalikis, Emmanuel N. Skountzos, Vlasis G. Mavrantzas
MATERIALS TODAY-PROCEEDINGS
(2018)