Macromolecular Theory and Simulations最新文献_第7页

Emergence and Stability of Hierarchical Structures under Cylindrical Confinement 圆柱约束下层次结构的产生与稳定性

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-05-18 DOI: 10.1002/mats.202370005

Tiancheng Chen, Yuci Xu

引用次数: 0

Masthead: Macromol. Theory Simul. 3/2023 刊头：Macromol。理论模拟。2023年3月

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Macromolecular Theory and Simulations Pub Date : 2023-05-18 DOI: 10.1002/mats.202370006

引用次数: 0

Coalescence of Sessile Polymer Droplets: A Molecular Dynamics Study 固定式聚合物液滴的聚结:分子动力学研究

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-05-12 DOI: 10.1002/mats.202300017

Soheil Arbabi, Panagiotis E. Theodorakis

引用次数: 2

On the Effective Lifetime of Reversible Bonds in Transient Networks 暂态网络中可逆键的有效寿命

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-05-05 DOI: 10.1002/mats.202300002

Sachin Shanbhag, Ralm G. Ricarte

{"title":"On the Effective Lifetime of Reversible Bonds in Transient Networks","authors":"Sachin Shanbhag, Ralm G. Ricarte","doi":"10.1002/mats.202300002","DOIUrl":"10.1002/mats.202300002","url":null,"abstract":"The renormalized bond lifetime model (RBLM) is a popular scaling theory for the effective lifetime of reversible bonds in transient networks. It recognizes that stickers connected by a reversible bond undergo many (J) cycles of dissociation and reassociation. After finally separating, one of these stickers finds a new open partner in time τopen via a subdiffusive process whose mean-squared displacement is proportional to tα, where t is the time elapsed, and α is the subdiffusion exponent. The RBLM makes convenient mathematical approximations to obtain analytical expressions for J and τopen. The consequences of relaxing these approximations is investigated by performing fractional Brownian motion (FBM) simulations. It is found that the scaling relations developed in the RBLM hold surprisingly well. However, RBLM overestimates both τopen and J, especially at lower values of α. For α = 0.5, corresponding to the Rouse limit, it is found that τopen is overestimated by a factor of approximately 4x, while the approximation for J is nearly exact. The degree of overestimation worsens as α decreases, and increases to 1–2 orders of magnitude at α = 0.25, corresponding to the reptation limit. This has important ramifications for experimental studies that use RBLM to interpret rheology and dielectric spectroscopy observations.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45558555","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}

引用次数: 2

Kelvin's Tetrakaidecahedron as a Wigner–Seitz Cell Found in Spherically Microphase-Separated BCC Lattice from AB Diblock Copolymer by Monte Carlo Simulation 用蒙特卡罗模拟在球形微相分离的BCC晶格和AB双嵌段共聚物中发现了维格纳-塞茨细胞的Kelvin四面体

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-05-04 DOI: 10.1002/mats.202300016

Jiro Suzuki, Yushu Matsushita

{"title":"Kelvin's Tetrakaidecahedron as a Wigner–Seitz Cell Found in Spherically Microphase-Separated BCC Lattice from AB Diblock Copolymer by Monte Carlo Simulation","authors":"Jiro Suzuki, Yushu Matsushita","doi":"10.1002/mats.202300016","DOIUrl":"10.1002/mats.202300016","url":null,"abstract":"Metropolis Monte–Carlo simulation is carried out for microphase-separated bulk state of AB diblock copolymers with various compositions. The distribution probability of end segments in long B-block chain are explored to determine the Wigner–Seitz(WS) cells as primitive cells for four known periodic structures, lamellar-, Gyroid-, cylindrical-, and spherical ones. The end segments are commonly turned to be localized at the several distinct far sites from the lattice points of WS cells for all morphologies investigated. Among them, when the fraction of A segments is 0.25, a hexagonal prism type column appears as a WS, while when the fraction is much lower at 0.1, body-centered cubic(BCC) lattice is formed and its end segments are found to be localized at hexagonal frames and also on the six square faces of truncated octahedron or Kelvin's Tetrakaidecahedron(KT), which has rarely been found in real soft material ever. This achievement is strongly pointing that each micelle formed by self-assembled diblock coplymers in bulk have essentially the framework of equivolume KT in real material systems.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202300016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43238022","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}

引用次数: 0

Kinetic Monte Carlo Simulations as a Tool for Unraveling the Impact of Solvent and Temperature on Polymer Topology for Self-Initiated Butyl Acrylate Radical Polymerizations at High Temperatures 动力学蒙特卡罗模拟作为揭示溶剂和温度对高温下自引发丙烯酸丁酯自由基聚合聚合物拓扑影响的工具

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-04-18 DOI: 10.1002/mats.202300007

Jonas Mätzig, Marco Drache, Georg Drache, Sabine Beuermann

{"title":"Kinetic Monte Carlo Simulations as a Tool for Unraveling the Impact of Solvent and Temperature on Polymer Topology for Self-Initiated Butyl Acrylate Radical Polymerizations at High Temperatures","authors":"Jonas Mätzig, Marco Drache, Georg Drache, Sabine Beuermann","doi":"10.1002/mats.202300007","DOIUrl":"10.1002/mats.202300007","url":null,"abstract":"High-temperature butyl acrylate polymerizations in bulk and in solution are investigated experimentally and by kinetic Monte Carlo (kMC) simulations. The experimental data comprise conversion-time data, molar mass distributions, and branching levels per polymer chain derived from size-exclusion chromatography with a multiangle laser light scattering detector. A kMC model is established, which allows for the description of the impact of solvent and temperature on molar mass distribution as well as type and content of macromonomers. Within the study kinetic coefficients for transfer to solvent and the thermal self-initiation of the monomer are determined according to the Metropolis Hastings algorithm. The kMC simulations provide information, which are otherwise not accessible, for example, the number of branch points per molecule as a function of molar mass or the molar mass distribution of various macromonomer species. Moreover, molar ratios of mid-chain and chain-end radicals are at hand for temperatures up to 160°C, which are important for the interpretation of the experimentally and via simulation-derived polymer topology as a function of molar masses.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202300007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47951207","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}

引用次数: 2

Dimensions of Network Polymers: Universal Relationship for the Ratio between Mean-Square Radius of Gyration and Graph Diameter 网络聚合物的尺寸：回转均方半径与图形直径之比的普遍关系

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-04-14 DOI: 10.1002/mats.202300012

Hidetaka Tobita

{"title":"Dimensions of Network Polymers: Universal Relationship for the Ratio between Mean-Square Radius of Gyration and Graph Diameter","authors":"Hidetaka Tobita","doi":"10.1002/mats.202300012","DOIUrl":"10.1002/mats.202300012","url":null,"abstract":"Mean-square radius of gyration Rg2 and the graph diameter D, which describe the dimensions of polymers, are investigated for the network polymers. Both for the random and nonrandom statistical networks whose cycle rank is r, a linear relationship Rg2 = ar D applies. The ratio ϕ of ar against the corresponding ring-free architecture a0, ϕr = ar/a0 has a universal relationship applicable both for the random and nonrandom networks with ϕr∝r−0.25 for large r’s, and an empirical relationship, ϕr = [(1 + r)−2/3 + r/2]−0.25 is proposed. For the polymer fraction having a given number of r, the nonrandom nature of crosslinking tends to make both Rg2 and D larger compared with the corresponding random networks, except for the limited cases with small values of r’s.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202300012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42805079","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}

引用次数: 0

Isolating the Effect of Crosslink Densities on Mechanical Properties of iPP Using DPD 用DPD分离交联密度对iPP力学性能的影响

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-04-13 DOI: 10.1002/mats.202300014

Yoshitake Suganuma, J. Elliott

引用次数: 0

Isolating the Effect of Crosslink Densities on Mechanical Properties of Isotactic Polypropylene Using Dissipative Particle Dynamics 用耗散粒子动力学分离交联密度对等规聚丙烯力学性能的影响

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-04-13 DOI: 10.1002/mats.202300014

Yoshitake Suganuma, James A. Elliott

{"title":"Isolating the Effect of Crosslink Densities on Mechanical Properties of Isotactic Polypropylene Using Dissipative Particle Dynamics","authors":"Yoshitake Suganuma, James A. Elliott","doi":"10.1002/mats.202300014","DOIUrl":"https://doi.org/10.1002/mats.202300014","url":null,"abstract":"Given the importance of preserving the mechanical properties of recycled isotactic polypropylene (iPP) during its processing, this work provides an improved understanding of the contribution of introducing physical or chemical crosslinks using the dissipative particle dynamics (DPD) method, which makes it possible to model iPP structures with a realistic range of crosslink densities. First, the protocol to build a coarse-grained model of iPP from an all-atom expression by Bayesian optimization is described. A Bayesian optimization procedure employing two different cutoff distances successfully provides optimal DPD parameters reproducing iPP's properties compared to the all-atom system. Then, the coarse-grained iPP model with optimal DPD parameters is applied to study structures containing a realistic range of crosslink densities to evaluate their mechanical properties. These calculations demonstrate that the mechanical properties such as the Young's modulus and ultimate strength increase while the fracture strain decreases with an increase in the crosslink density, which is consistent with experimental observations. The results also show that there is a critical crosslink density above which these properties start to be improved due to the introduction of crosslinks. These findings can help us to obtain targeted properties of recycled iPP by introducing physical or chemical crosslinks.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202300014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50130998","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}

引用次数: 0

Volumetric and Energetic Properties of Polystyrene and Polyethylene Oxide Affected by Thermal Cycling 热循环对聚苯乙烯和聚氧乙烯体积和能量性能的影响

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-04-06 DOI: 10.1002/mats.202300008

Benoit Minisini, Armand Soldera

{"title":"Volumetric and Energetic Properties of Polystyrene and Polyethylene Oxide Affected by Thermal Cycling","authors":"Benoit Minisini, Armand Soldera","doi":"10.1002/mats.202300008","DOIUrl":"10.1002/mats.202300008","url":null,"abstract":"Polymers are known to exhibit hysteresis in their thermal and volumetric properties between cooling and heating at the glass transition. A thorough investigation of this hysteresis using atomistic simulation is not proposed until now. In this work, therefore, the glass transition is studied through heating and cooling protocols at constant rate for two polymers, polystyrene (PS) and polyethylene oxide (PEO), with different molecular weights. To achieve this objective, the analysis is carried out by plotting against temperature, specific volume, coefficient of thermal expansion, total energy, and constant volume heat capacity. The calculated properties for PS and PEO are found to be in good agreement with experimental data, confirming the accuracy of the TraPPE force field for these polymers. The glass transition temperature (Tg) range remains the same regardless of the properties. Moreover, the difference in properties between heating and cooling processes systematically leads to a peak at the same temperature, associated with Tg. Finally, starting from a low temperature, the polymer chains remain mainly in a potential well as the temperature rises, while during cooling the exploration of the configuration space continues up to the temperature where no torsional changes are observed.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202300008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45275990","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}

引用次数: 1