Macromolecular Theory and Simulations最新文献

Front Cover: Macromol. Theory Simul. 4/2025 封面：Macromol。理论模拟，4/2025

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2025-07-22 DOI: 10.1002/mats.70010

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Issue Information: Macromol. Theory Simul. 4/2025 发布信息：Macromol。理论模拟，4/2025

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2025-07-22 DOI: 10.1002/mats.70009

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A Comparison of Bead-Spring and Site-Binding Models for Weak Polyelectrolytes 弱聚电解质珠-弹簧和位点结合模型的比较

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2025-05-28 DOI: 10.1002/mats.202500020

Loris Burth, David Beyer, Christian Holm

{"title":"A Comparison of Bead-Spring and Site-Binding Models for Weak Polyelectrolytes","authors":"Loris Burth, David Beyer, Christian Holm","doi":"10.1002/mats.202500020","DOIUrl":"https://doi.org/10.1002/mats.202500020","url":null,"abstract":"Understanding the ionization behavior of weak polyelectrolytes in aqueous solutions with added salt is crucial for designing advanced materials. Predicting the ionization states of weak polyelectrolyte is challenging due to the interplay between long-range Coulomb interactions, conformational flexibility, and chemical equilibria. Bead-spring models with explicit ion treatment provide accurate results but are computationally expensive. In contrast, Ising-like site-binding models are computationally efficient but neglect conformational flexibility and use an implicit salt description. To assess the validity of these approximations, a site-binding model is compared with bead-spring models that include implicit and explicit ion treatments. These results show that under strong electrostatic coupling, explicit ion treatment is critical for accurately modeling ionization behavior. Both the site-binding and implicit bead-spring models overestimate monomer correlations in this regime, leading to significant deviations from the explicit bead-spring model. Under weak coupling, typical of aqueous environments with monovalent salts, all models give reasonable ionization curves, with slight differences. The implicit bead-spring model shows slightly stronger suppression of ionization, while the site-binding model aligns more closely with the explicit bead-spring model due to compensating errors in ion treatment and flexibility. In conclusion, while all models perform well under weak coupling, explicit ion treatment is essential for accurate ionization under strong coupling.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202500020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144673187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Numerical Simulation and Analysis of CO2 Bubble Deformation in PET Continuous Extrusion Process PET连续挤压过程CO2气泡变形的数值模拟与分析

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2025-05-21 DOI: 10.1002/mats.202500006

Lihua Cai, Wangyongjia Zhong, Haifeng Fang, Zheng Rong, Sipeng Zhang

{"title":"Numerical Simulation and Analysis of CO2 Bubble Deformation in PET Continuous Extrusion Process","authors":"Lihua Cai, Wangyongjia Zhong, Haifeng Fang, Zheng Rong, Sipeng Zhang","doi":"10.1002/mats.202500006","DOIUrl":"https://doi.org/10.1002/mats.202500006","url":null,"abstract":"In this paper, the dynamic deformation of supercritical CO2 bubbles in the shear flow field of polyethylene terephthalate (PET) is analyzed, and the dynamic continuous extrusion process of PET microcellular foaming is numerically simulated. The extrusion process of PET supercritical CO2 homogeneous solution is simulated by the user defined function (UDF) program, and the volume of fluid (VOF) method is used to track the gas-liquid interface. The deformation of supercritical CO2 bubbles in the PET microcellular foaming extrusion process is simulated in FLUENT software. It is found that in the continuous dynamic extrusion process, the bubble moves with the polymer at a certain angle, and there will be an area at the two ends to inhibit the shear thinning of the melt, which affects the movement pattern of the bubble. The increase in shear rate is the main factor causing the increase in the aspect ratio of the bubble. The increase of the rheological index can promote the bubble to maintain the spherical shape by affecting the shear flow field around the bubble. In addition, it is found that the effect of surface tension on bubble morphology in the shear flow field is not as large as that in the static flow field.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144672798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Issue Information: Macromol. Theory Simul. 3/2025 发布信息：Macromol。理论模拟3/2025

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2025-05-19 DOI: 10.1002/mats.202570006

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Computational Modeling of the Continuous Separation of a Molten Polymer Mixture in a Centrifugal Field 熔融聚合物混合物在离心场中连续分离的计算模型

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2025-05-19 DOI: 10.1002/mats.202570005

V. Medvid, H. Steiner, C. Irrenfried, M. Feuchter, G. Brenn

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Numerical Simulation of Mixing Enhancement in a Single Screw Extruder by Different Internal Baffles 不同内挡板对单螺杆挤出机混合增强的数值模拟

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2025-05-12 DOI: 10.1002/mats.202500009

Huiwen Yu, Yuanyao Wang, Lingcao Tan, Jiarong Huang, Baiping Xu

{"title":"Numerical Simulation of Mixing Enhancement in a Single Screw Extruder by Different Internal Baffles","authors":"Huiwen Yu, Yuanyao Wang, Lingcao Tan, Jiarong Huang, Baiping Xu","doi":"10.1002/mats.202500009","DOIUrl":"https://doi.org/10.1002/mats.202500009","url":null,"abstract":"The metering section of an industrial-scale single screw extruder is modeled, and two kinds of discontinuous baffles, three rows of plate baffles, and two types of plow-shaped baffles, arranged in staggered or parallel ways, are proposed to improve the distributive and dispersive mixing. Considering the narrow gap between the screw and barrel, the finite element method along with the mesh superposition technique is applied to solve fully 3D isothermal flow fields where the fluid is assumed to obey the Carreau constitutive model. The computation codes are successfully developed to achieve particle tracking using the fourth-order Runge–Kutta scheme. Distributive mixing is evaluated in terms of the evolution of tracer particles and Poincaré sections. Dispersive mixing is then examined in terms of shear rates, mixing index, distribution probability function of mixing index, and its integral function for particles tracking with time. For the same pressure drop and the same screw rotating speed, when compared to the conventional single screw, the numerical simulation results showed that the screw with staggered plow-shaped baffles achieved better distributive mixing with the output nearly unchanged while three rows of plate baffles significantly enhanced both distributive and dispersive mixing at the cost of output reduction by 13.2%.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202500009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144672816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Efficient Computation of Single-Chain Partition Functions in Field-Theoretic Simulations of Polymers With Nested Tree-Like Topologies 嵌套树状拓扑聚合物场理论模拟中单链配分函数的高效计算

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2025-05-12 DOI: 10.1002/mats.202500023

Charles Li, Kris T. Delaney, M. Scott Shell, Glenn H. Fredrickson

{"title":"Efficient Computation of Single-Chain Partition Functions in Field-Theoretic Simulations of Polymers With Nested Tree-Like Topologies","authors":"Charles Li, Kris T. Delaney, M. Scott Shell, Glenn H. Fredrickson","doi":"10.1002/mats.202500023","DOIUrl":"https://doi.org/10.1002/mats.202500023","url":null,"abstract":"A general algorithm is introduced to compute single-chain partition functions in field-theoretic simulations of polymers with nested tree-like topologies, including self-consistent field theory simulations that invoke the mean-field approximation. The algorithm is an extension of a method used in a number of recent studies on the phase behavior of bottlebrush block copolymers. In those studies, the computational cost of computing single-chain partition functions is reduced by aggregating the statistical weight of degenerate side arms. By extending this method to chains with arbitrary degrees of branching, the computational cost is reduced to scale with the total length of unique segments in the chain instead of the total length/mass of the entire chain. The method is first validated on a model dendrimer system by comparing results to coarse-grained molecular dynamics simulations and also demonstrate its advantage over more conventional approaches to compute single-chain partition functions. The algorithm is subsequently used to analyze the phase behavior of a molecularly informed field-theoretic model of poly(butyl acrylate)-graft-poly(dodecyl acrylate) (pBA-graft-pDDA) copolymers in a dodecane solvent. The methodology can help advance field-theoretic investigations of branched polymers by leveraging degeneracy in the chain to reduce computational cost and avoid the need to develop architecture-specific algorithms.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144672809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Determination of the Kinetic Parameters of Condensed Phase Reactions Using Chebyshev Series Expansion 用切比雪夫级数展开测定凝聚相反应的动力学参数

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2025-04-08 DOI: 10.1002/mats.202500001

Alireza Aghili, Amir Hossein Haghighi, Amir Hossein Shabani

{"title":"Determination of the Kinetic Parameters of Condensed Phase Reactions Using Chebyshev Series Expansion","authors":"Alireza Aghili, Amir Hossein Haghighi, Amir Hossein Shabani","doi":"10.1002/mats.202500001","DOIUrl":"https://doi.org/10.1002/mats.202500001","url":null,"abstract":"In the investigation of condensed phase reactions, obtaining kinetic parameters is vital for understanding reaction behavior and optimizing conditions. To achieve this, differential methods have been devised, yet due to the instability of calculating instantaneous reaction rates through numerical differentiation, they have been less commonly utilized. In this study, the extraction of smooth reaction rate curves from highly noisy experimental data via the Chebyshev series expansion (CSE) approach is explained. Furthermore, a novel combined kinetic analysis is developed to determine reaction kinetic parameters utilizing the Chebyshev series expansion. By employing the new method, kinetic parameters can be accurately deduced by performing multiple linear regression analysis on kinetic data generated from reactions. The CSE has consistently exhibited exceptional accuracy in approximating the conversion function. The primary advantage of the new method lies in its ability to accurately determine unique values for kinetic parameters, including activation energy, pre-exponential factor, and conversion function, without prior knowledge of the reaction mechanism. The new method has been validated using kinetic data from a simulated reaction and poly(methyl methacrylate) thermal degradation. To facilitate readers in applying the new methods to various kinetic data, the GNU Octave/MATLAB codes have been made publicly available.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144091280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Computational Modeling of the Continuous Separation of a Molten Polymer Mixture in a Centrifugal Field 熔融聚合物混合物在离心场中连续分离的计算模型

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2025-03-26 DOI: 10.1002/mats.202400109

V. Medvid, H. Steiner, C. Irrenfried, M. Feuchter, G. Brenn

{"title":"Computational Modeling of the Continuous Separation of a Molten Polymer Mixture in a Centrifugal Field","authors":"V. Medvid, H. Steiner, C. Irrenfried, M. Feuchter, G. Brenn","doi":"10.1002/mats.202400109","DOIUrl":"https://doi.org/10.1002/mats.202400109","url":null,"abstract":"A technique for separating molten polymer blends is investigated computationally. The device includes a rotating cylinder, separating the mixture components with different densities by the centrifugal force. Molten LDPE (Low-Density Poly(Ethylene)) and PET (Poly(Ethylene) Terephthalate) mixtures are investigated. The computational modeling is intended to evaluate the feasibility of such a technique at the time and length scales studied. A dispersed mixture model accounts for the immiscibility of the mixture components. The CFD simulations provide the field distributions of the flow field variables and of the mixture component fractions. The outlet composition and separation efficiency in the steady-state process, and the different process parameter influences on the process result, are studied. The polymer system at hand represents blends of postconsumer plastics. The study can therefore contribute to the development of a novel method for plastic waste recycling. With continuous feed and extraction of the polymer streams, the process can be automated.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202400109","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144091665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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