Yiwen Zheng, Jiankang Wang, Chenyang Wang, Zhijun Li, Zuliang Yang
Front Cover: The rheological parameters are important factors influencing mixing of polymer blends. The tracer particle method is used to represent the mixing effect of the melt, the flow of virtual material/thermoplastic polyurethanes with high and low viscosities in dynamic mixers are simulated. The patterns of zero shear viscosity ratio, relaxation time ratio and non-Newtonian index ratio influencing the mixing are discovered. More details can be found in article 2400031 by Jiankang Wang and co-workers.
{"title":"Investigating the Effect of Rheological Parameter Ratios on the Mixing Properties of TPU Blends","authors":"Yiwen Zheng, Jiankang Wang, Chenyang Wang, Zhijun Li, Zuliang Yang","doi":"10.1002/mats.202470009","DOIUrl":"https://doi.org/10.1002/mats.202470009","url":null,"abstract":"<p><b>Front Cover</b>: The rheological parameters are important factors influencing mixing of polymer blends. The tracer particle method is used to represent the mixing effect of the melt, the flow of virtual material/thermoplastic polyurethanes with high and low viscosities in dynamic mixers are simulated. The patterns of zero shear viscosity ratio, relaxation time ratio and non-Newtonian index ratio influencing the mixing are discovered. More details can be found in article 2400031 by Jiankang Wang and co-workers.\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202470009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142234970","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}
{"title":"Masthead: Macromol. Theory Simul. 5/2024","authors":"","doi":"10.1002/mats.202470010","DOIUrl":"https://doi.org/10.1002/mats.202470010","url":null,"abstract":"","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202470010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142234881","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}
This study introduces a rheological equivalent circuit model inspired by electrochemical impedance spectroscopy (EIS) to analyze complex viscosity data. By exploiting the similarity between the Cole–Cole plot in rheology and the Nyquist plot in EIS, the study adopts circuit fitting methodologies to interpret rheological behavior of various polymers. The model employs redefined electrochemical elements, including dashpots, springs, rheological constant phase elements, and Warburg elements, to capture both linear and non‐linear responses. This approach offers both analytical and predictive capabilities, providing new insights into material composition.
{"title":"Rheological Equivalent Circuit Model Using Electrochemical Impedance Analysis","authors":"Hwan Woo Choi, Young Seok Song","doi":"10.1002/mats.202400069","DOIUrl":"https://doi.org/10.1002/mats.202400069","url":null,"abstract":"This study introduces a rheological equivalent circuit model inspired by electrochemical impedance spectroscopy (EIS) to analyze complex viscosity data. By exploiting the similarity between the Cole–Cole plot in rheology and the Nyquist plot in EIS, the study adopts circuit fitting methodologies to interpret rheological behavior of various polymers. The model employs redefined electrochemical elements, including dashpots, springs, rheological constant phase elements, and Warburg elements, to capture both linear and non‐linear responses. This approach offers both analytical and predictive capabilities, providing new insights into material composition.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207028","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}
Jin Huang, Xiaorong Ma, Hongyao Li, Mengxue Liu, Qinghe Gao, Cuiqin Li
Polymer flooding, using hydrolyzed polyacrylamide (HPAM), is crucial in enhanced oil recovery technology. The effect of the HPAM and NaCl concentration on the stability of the simulated emulsions was assessed through multiple light scattering experiments. The results demonstrated that HPAM significantly enhanced the stability of both oil‐in‐water (O/W) and water‐in‐oil (W/O) emulsions. The HPAM concentration escalated from 200 mg L−1 to 1000 mg L−1, increasing from 1.24% to 1.31% at 60 minute in the average backscattering of W/O emulsions. The average transmittance of O/W emulsions exhibited a significant decline from 2.54% to 0.12%. The NaCl concentration had a small effect on the stability of the emulsions. Molecular dynamics simulations revealed that HPAM adsorbed at the oil water interface by the point‐like nature, with stronger interaction between its amide group and the oil molecule than its carboxyl group. The hydrogen bond number and the hydrogen bond lifetime of HPAM‐H2O and HPAM‐HPAM increase with increasing the number of HPAM molecules at the oil‐water interface, slowing diffusion coefficient of water molecules and increasing the interface thickness. Increasing salinity can weaken the HPAM‐water interaction, reducing the emulsification stability. This work provides insights into the emulsification characteristics and mechanisms of HPAM.
{"title":"Effect of Hydrolyzed Polyacrylamide on the Emulsion Stability by Multiple Light Scattering and Molecular Dynamics Simulation","authors":"Jin Huang, Xiaorong Ma, Hongyao Li, Mengxue Liu, Qinghe Gao, Cuiqin Li","doi":"10.1002/mats.202400040","DOIUrl":"https://doi.org/10.1002/mats.202400040","url":null,"abstract":"Polymer flooding, using hydrolyzed polyacrylamide (HPAM), is crucial in enhanced oil recovery technology. The effect of the HPAM and NaCl concentration on the stability of the simulated emulsions was assessed through multiple light scattering experiments. The results demonstrated that HPAM significantly enhanced the stability of both oil‐in‐water (O/W) and water‐in‐oil (W/O) emulsions. The HPAM concentration escalated from 200 mg L<jats:sup>−1</jats:sup> to 1000 mg L<jats:sup>−1</jats:sup>, increasing from 1.24% to 1.31% at 60 minute in the average backscattering of W/O emulsions. The average transmittance of O/W emulsions exhibited a significant decline from 2.54% to 0.12%. The NaCl concentration had a small effect on the stability of the emulsions. Molecular dynamics simulations revealed that HPAM adsorbed at the oil water interface by the point‐like nature, with stronger interaction between its amide group and the oil molecule than its carboxyl group. The hydrogen bond number and the hydrogen bond lifetime of HPAM‐H<jats:sub>2</jats:sub>O and HPAM‐HPAM increase with increasing the number of HPAM molecules at the oil‐water interface, slowing diffusion coefficient of water molecules and increasing the interface thickness. Increasing salinity can weaken the HPAM‐water interaction, reducing the emulsification stability. This work provides insights into the emulsification characteristics and mechanisms of HPAM.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207029","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}
Often the errors in the measurement of copolymerizations are not accurately determined or included in the calculation of reactivity ratios. Some knowledge of the errors in the initial monomer ratio, conversion, and copolymer composition is however essential to obtain reliable (unbiased) reactivity ratios with a realistic uncertainty. It is shown that the errors serve a trifold purpose; they can serve as weighing factors in the fit, they can be compared with the fit residues to decide whether the chosen model is adequate for the data and they can be used to construct a realistic joint confidence interval for the reactivity ratios. The best approach is to have an estimate of the individual errors in the copolymer composition, either from a thorough error propagation exercise or from replicate measurements. With these errors, the χ2‐joint confidence intervals can then be constructed which gives a realistic estimate of the errors in the reactivity ratios. Utilizing the Errors in Variables Method (EVM) is correct and useful, but only if the individual errors in all the variables in each experiment are more or less known.
{"title":"The Importance of the Knowledge of Errors in the Measurements in the Determination of Copolymer Reactivity Ratios from Composition Data","authors":"Alexander Maria van Herk, Quan Liu","doi":"10.1002/mats.202400043","DOIUrl":"https://doi.org/10.1002/mats.202400043","url":null,"abstract":"Often the errors in the measurement of copolymerizations are not accurately determined or included in the calculation of reactivity ratios. Some knowledge of the errors in the initial monomer ratio, conversion, and copolymer composition is however essential to obtain reliable (unbiased) reactivity ratios with a realistic uncertainty. It is shown that the errors serve a trifold purpose; they can serve as weighing factors in the fit, they can be compared with the fit residues to decide whether the chosen model is adequate for the data and they can be used to construct a realistic joint confidence interval for the reactivity ratios. The best approach is to have an estimate of the individual errors in the copolymer composition, either from a thorough error propagation exercise or from replicate measurements. With these errors, the χ<jats:sup>2</jats:sup>‐joint confidence intervals can then be constructed which gives a realistic estimate of the errors in the reactivity ratios. Utilizing the Errors in Variables Method (EVM) is correct and useful, but only if the individual errors in all the variables in each experiment are more or less known.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207030","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}
Orlando Villegas, Marta Serrano Martínez, Laura Le Bras, Alistar Ottochian, Nicolas Pineau, Aurélie Perrier, Claire A. Lemarchand
Light‐responsive shape‐changing polymers are photonastic materials: they can convert light into mechanical energy through macroscopic transformations. Indeed, photochromic molecules embedded in these polymer films present light‐induced structural modifications that can trigger a significant macroscopic deformation. In this theoretical study based on molecular dynamics simulations, analysis tools ranging from atomic to supramolecular scales are developed to investigate this photonastic phenomenon. To this purpose, a model system built upon an azobenzene photochrome embedded in different environments (tetrahydrofuran, cis‐1,4‐polybutadiene and hydroxyl‐terminated polybutadiene) is considered. First, the impact of the environment on the photochrome properties is discussed through the analysis of the structural properties, ultra‐violet visible (UV–vis) absorption spectra and dynamical properties of the photoswitch. Then, the impact of the presence of the photochrome on the polymer is studied. At the atomic scale, the radial distribution functions show some differences between the cis and trans isomers due to geometrical effects. At the molecular scale, the analysis of the size and shape of the polymer chains reveals that the photochrome has no impact on the chain properties. Finally, at the macroscopic scale, the cohesive energy density shows that the polymer is stabilized by the presence of photochrome molecules.
{"title":"Mechanical Effect Produced by Photo‐Switchable Reactions: Insights from Molecular Simulations","authors":"Orlando Villegas, Marta Serrano Martínez, Laura Le Bras, Alistar Ottochian, Nicolas Pineau, Aurélie Perrier, Claire A. Lemarchand","doi":"10.1002/mats.202400033","DOIUrl":"https://doi.org/10.1002/mats.202400033","url":null,"abstract":"Light‐responsive shape‐changing polymers are photonastic materials: they can convert light into mechanical energy through macroscopic transformations. Indeed, photochromic molecules embedded in these polymer films present light‐induced structural modifications that can trigger a significant macroscopic deformation. In this theoretical study based on molecular dynamics simulations, analysis tools ranging from atomic to supramolecular scales are developed to investigate this photonastic phenomenon. To this purpose, a model system built upon an azobenzene photochrome embedded in different environments (tetrahydrofuran, cis‐1,4‐polybutadiene and hydroxyl‐terminated polybutadiene) is considered. First, the impact of the environment on the photochrome properties is discussed through the analysis of the structural properties, ultra‐violet visible (UV–vis) absorption spectra and dynamical properties of the photoswitch. Then, the impact of the presence of the photochrome on the polymer is studied. At the atomic scale, the radial distribution functions show some differences between the cis and trans isomers due to geometrical effects. At the molecular scale, the analysis of the size and shape of the polymer chains reveals that the photochrome has no impact on the chain properties. Finally, at the macroscopic scale, the cohesive energy density shows that the polymer is stabilized by the presence of photochrome molecules.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141870406","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}
Abdullahi Moyosore, Haslina Ahmad, Muhammad Alif Muhammad Latif, Mostafa Yousefzadeh Borzehandani, Mohd Basyaruddin AbdulRahman, Emilia Abdelmalek
Metal‐organic frameworks (MOFs) have emerged as versatile materials with exceptional properties, including high porosities, large surface areas, and remarkable stabilities, making them attractive for various applications. MOF‐5 stands out for its thermal stability and surface area, making it promising for diverse applications, including drug delivery and gas adsorption. This study explores the potential of amino acid MOF (AA‐MOF) composites, integrating phenylalanine, tryptophan, and tyrosine, for selective CO2 and CH4 adsorption using grand canonical Monte Carlo (GCMC) simulations. The impact of amino acid composition and spatial arrangement within MOF‐5 on selective CO2 and CH4 adsorption performance have been investigated. The results indicate that tryptophan‐MOF‐5 exhibits the highest CO2 uptake due to the interaction between CO2 and tryptophan, while phenylalanine‐MOF‐5 demonstrated the lowest affinity for gas adsorption. Radial distribution function (RDF) analysis reveals distinct gas distribution patterns within the composites, with tryptophan playing a dominant role in gas adsorption. Additionally, analysis of total energy, enthalpy of adsorption, and Henry's coefficient provide insights into the thermodynamic aspects of gas adsorption onto AA‐MOF composites. This study enhances the understanding of the fundamental mechanisms underlying CO2 and CH4 selective adsorption in amino acid MOF composites, facilitating the development of efficient gas separation technologies.
金属有机框架（MOFs）是一种多用途材料，具有高孔隙率、大比表面积和卓越的稳定性等优异特性，因此在各种应用领域都具有吸引力。MOF-5 以其热稳定性和比表面积脱颖而出，在药物输送和气体吸附等多种应用领域大有可为。本研究利用大规范蒙特卡洛（GCMC）模拟，探讨了氨基酸 MOF（AA-MOF）复合材料（包括苯丙氨酸、色氨酸和酪氨酸）选择性吸附 CO2 和 CH4 的潜力。研究了 MOF-5 中氨基酸组成和空间排列对二氧化碳和甲烷选择性吸附性能的影响。结果表明，由于 CO2 与色氨酸之间的相互作用，色氨酸-MOF-5 对 CO2 的吸收率最高，而苯丙氨酸-MOF-5 对气体的吸附亲和力最低。径向分布函数（RDF）分析揭示了复合材料中独特的气体分布模式，色氨酸在气体吸附中起主导作用。此外，对总能量、吸附焓和亨利系数的分析还有助于深入了解 AA-MOF 复合材料对气体吸附的热力学特性。这项研究加深了人们对氨基酸 MOF 复合材料中二氧化碳和甲烷选择性吸附基本机制的理解，有助于开发高效的气体分离技术。
{"title":"Potential of Phenylalanine‐, Tryptophan‐, and Tyrosine‐MOF‐5 Composites for Selective Carbon Dioxide and Methane Adsorption","authors":"Abdullahi Moyosore, Haslina Ahmad, Muhammad Alif Muhammad Latif, Mostafa Yousefzadeh Borzehandani, Mohd Basyaruddin AbdulRahman, Emilia Abdelmalek","doi":"10.1002/mats.202400051","DOIUrl":"https://doi.org/10.1002/mats.202400051","url":null,"abstract":"Metal‐organic frameworks (MOFs) have emerged as versatile materials with exceptional properties, including high porosities, large surface areas, and remarkable stabilities, making them attractive for various applications. MOF‐5 stands out for its thermal stability and surface area, making it promising for diverse applications, including drug delivery and gas adsorption. This study explores the potential of amino acid MOF (AA‐MOF) composites, integrating phenylalanine, tryptophan, and tyrosine, for selective CO<jats:sub>2</jats:sub> and CH<jats:sub>4</jats:sub> adsorption using grand canonical Monte Carlo (GCMC) simulations. The impact of amino acid composition and spatial arrangement within MOF‐5 on selective CO<jats:sub>2</jats:sub> and CH<jats:sub>4</jats:sub> adsorption performance have been investigated. The results indicate that tryptophan‐MOF‐5 exhibits the highest CO<jats:sub>2</jats:sub> uptake due to the interaction between CO<jats:sub>2</jats:sub> and tryptophan, while phenylalanine‐MOF‐5 demonstrated the lowest affinity for gas adsorption. Radial distribution function (RDF) analysis reveals distinct gas distribution patterns within the composites, with tryptophan playing a dominant role in gas adsorption. Additionally, analysis of total energy, enthalpy of adsorption, and Henry's coefficient provide insights into the thermodynamic aspects of gas adsorption onto AA‐MOF composites. This study enhances the understanding of the fundamental mechanisms underlying CO<jats:sub>2</jats:sub> and CH<jats:sub>4</jats:sub> selective adsorption in amino acid MOF composites, facilitating the development of efficient gas separation technologies.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783798","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}
Yulong Wang, Tong Liu, Meng Wang, Lili Li, Junguo Gao, Ning Guo, Defeng Zang, Ji Liu
The critical frequency and the relaxation time are analyzed through deformation and displacement during electrostriction which is induced by the electrical field at different frequencies. First, when the frequency is 50 Hz and the field strength is 2.5 kV mm−1, the electrostrictive displacement of polyethylene is 6.72 × 10−4 mm. After the data fitting, it is found that the displacement increases linearly with the square of field strength and that the proportional coefficient of 50 Hz is 1.08 × 10−4. Second, due to the influence of relaxation polarization and power loss, with the increase of frequency, the displacement and the proportional coefficient first increases then decreases, and when the frequency is 10 kHz, the displacement of 2.20 × 10−6 mm and the proportional coefficient of 3.51 × 10−7 have minimum values, which are 99.67% and 99.68% lower than that of 50 Hz, respectively. There is the critical frequency. Finally, based on the characteristic of anomalous dispersion, the relaxation time of polyethylene is 9.19 × 10−6s, which is in the time range of thermionic relaxation polarization and consistent with the actual situation. This analysis confirms the quantitative relationship between electrostrictive characteristics, field strength, and polarization. In addition, the relationship between frequency and strain is discussed, and the critical frequency in polymer and the relaxation time are confirmed.
{"title":"Simulation on Critical Frequency of Polymer in Electrostrictive Properties","authors":"Yulong Wang, Tong Liu, Meng Wang, Lili Li, Junguo Gao, Ning Guo, Defeng Zang, Ji Liu","doi":"10.1002/mats.202400045","DOIUrl":"https://doi.org/10.1002/mats.202400045","url":null,"abstract":"The critical frequency and the relaxation time are analyzed through deformation and displacement during electrostriction which is induced by the electrical field at different frequencies. First, when the frequency is 50 Hz and the field strength is 2.5 kV mm<jats:sup>−1</jats:sup>, the electrostrictive displacement of polyethylene is 6.72 × 10<jats:sup>−4</jats:sup> mm. After the data fitting, it is found that the displacement increases linearly with the square of field strength and that the proportional coefficient of 50 Hz is 1.08 × 10<jats:sup>−4</jats:sup>. Second, due to the influence of relaxation polarization and power loss, with the increase of frequency, the displacement and the proportional coefficient first increases then decreases, and when the frequency is 10 kHz, the displacement of 2.20 × 10<jats:sup>−6</jats:sup> mm and the proportional coefficient of 3.51 × 10<jats:sup>−7</jats:sup> have minimum values, which are 99.67% and 99.68% lower than that of 50 Hz, respectively. There is the critical frequency. Finally, based on the characteristic of anomalous dispersion, the relaxation time of polyethylene is 9.19 × 10<jats:sup>−6</jats:sup>s, which is in the time range of thermionic relaxation polarization and consistent with the actual situation. This analysis confirms the quantitative relationship between electrostrictive characteristics, field strength, and polarization. In addition, the relationship between frequency and strain is discussed, and the critical frequency in polymer and the relaxation time are confirmed.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783587","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}
The entanglement length plays a key role in deciding many important properties of thermoplastics. A number of computational techniques exist for the determination of entanglement length. In Ahmad et al.,[1] a method is proposed that treats a macromolecular chain as a 1D open curve and identifies entanglements by computing the linking number between two such interacting curves. If the curves wind around each other, a topological entanglement is detected. However, the entanglement length that is measured in experiments is assumed to be between rheological entanglements, which are clusters of such topological entanglements that collectively anchor the interacting chains strongly. In this article, the method of clustering topological entanglements into rheological ones is further elaborated and the robustness of the method is assessed. It is shown that this method estimates an entanglement length that depends on the forcefield chosen and is reasonably constant for chain lengths longer than the entanglement length. For shorter chain lengths, the method returns an infinite value of entanglement length indicating that the sample is unentangled. Moreover, in spite of using a geometry‐based algorithm for clustering topological entanglements, the estimated entanglement length retains known empirical connections with physical attributes associated with the ensemble.
{"title":"An Algorithm for Computing Entanglements in an Ensemble of Linear Polymers","authors":"Pramod Kumar Patel, Sumit Basu","doi":"10.1002/mats.202400035","DOIUrl":"https://doi.org/10.1002/mats.202400035","url":null,"abstract":"The entanglement length plays a key role in deciding many important properties of thermoplastics. A number of computational techniques exist for the determination of entanglement length. In Ahmad et al.,<jats:sup>[1]</jats:sup> a method is proposed that treats a macromolecular chain as a 1D open curve and identifies entanglements by computing the linking number between two such interacting curves. If the curves wind around each other, a topological entanglement is detected. However, the entanglement length that is measured in experiments is assumed to be between rheological entanglements, which are clusters of such topological entanglements that collectively anchor the interacting chains strongly. In this article, the method of clustering topological entanglements into rheological ones is further elaborated and the robustness of the method is assessed. It is shown that this method estimates an entanglement length that depends on the forcefield chosen and is reasonably constant for chain lengths longer than the entanglement length. For shorter chain lengths, the method returns an infinite value of entanglement length indicating that the sample is unentangled. Moreover, in spite of using a geometry‐based algorithm for clustering topological entanglements, the estimated entanglement length retains known empirical connections with physical attributes associated with the ensemble.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785992","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}
{"title":"Front Cover: Macromol. Theory Simul. 4/2024","authors":"","doi":"10.1002/mats.202470007","DOIUrl":"https://doi.org/10.1002/mats.202470007","url":null,"abstract":"","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202470007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141730294","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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