{"title":"A Comprehensive Monte Carlo Model of the Grafting of Maleic Anhydride onto Polypropylene with Experimental Validation","authors":"Tomás Romero Pietrafesa, Adriana Brandolin, Claudia Sarmoria, Mariano Asteasuain","doi":"10.1002/mats.202300018","DOIUrl":"10.1002/mats.202300018","url":null,"abstract":"<p>A Monte Carlo model is employed to investigate the grafting of maleic anhydride onto polypropylene using a peroxide initiator. The study aimed to develop a comprehensive model that considered a very detailed kinetic mechanism, including chain transfer to polymer, homopolymerization as well as several copolymer reactions. The relative importance of these reactions is evaluated using a sensitivity analysis, which identified homopolymerization, <i>β</i>-scission, chain grafting, and termination by disproportionation as the most influential reactions. The kinetic constants of these reactions are tuned to fit reported experimental data using the Surface Response Method. The model considers a pseudo-homogeneous reaction medium and predicts average molecular weights, degree of grafting, molecular weight distribution, and grafting distribution. Furthermore, model simulations provided useful information about the impact of initial concentrations of reactants and reaction time on the molecular properties of the grafted polymer.</p>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 5","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44426847","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":"Dynamics Responses of Graphene Nanoplatelets Reinforced Polydimethylsiloxane (PDMS) Nanocomposites: A Molecular Dynamics Study","authors":"Zheng Li, Tong Li, Kecheng Zhang, Bo Wang","doi":"10.1002/mats.202300021","DOIUrl":"https://doi.org/10.1002/mats.202300021","url":null,"abstract":"","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43393041","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":"Dynamics Responses of Graphene Nanoplatelets-Reinforced Polydimethylsiloxane Nanocomposites: A Molecular Dynamics Study","authors":"Zheng Li, Tong Li, Ke Zhang, Bo Wang","doi":"10.1002/mats.202300021","DOIUrl":"https://doi.org/10.1002/mats.202300021","url":null,"abstract":"<p>Molecular dynamics method is employed to characterize the mechanical properties of polydimethylsiloxane (PDMS) materials reinforced by graphene nanoplatelets (GNPs). Modeling results demonstrate that the addition of GNPs to PDMS significantly improves the damping properties of PDMS at high temperatures. The underlying physical mechanism is further investigated, and it is found that the interfacial interactions between the GNPs and PDMS play a crucial role in the energy dissipation capabilities. At elevated temperatures, a decrease in the interaction energy between the GNPs and PDMS matrix is observed, increasing the interfacial shipment, and improving the energy dissipation. In addition, GNPs will reflect more impact energy at a higher temperature. This study provides valuable insights into the use of GNPs for the improvement of the damping performance of PDMS materials at high temperatures.</p>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 5","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50126956","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":"Dimerization of Polyglutamine within the PRIME20 Model using Stochastic Approximation Monte Carlo","authors":"Christian Lauer, Wolfgang Paul","doi":"10.1002/mats.202200075","DOIUrl":"10.1002/mats.202200075","url":null,"abstract":"<p>This study presents a numerical investigation of the dimerization of polyglutamine homo-peptides of varying length. It employs the PRIME20 intermediate resolution protein model and studies it with a flat-histogram type Monte Carlo simulation that gives access to the thermodynamic equilibrium of this model over the complete control parameter range (for the simulations this is temperature). For densities comparable to typical in vitro experimental conditions, this study finds that the aggregation and folding of the polyglutamine chains occur concurrently. However, as a function of chain length the sequence of establishment of intra- and intermolecular hydrogen bonding contacts changes. Chains longer than about <i>N</i> = 24 polyglutamine repeat units fold first and then aggregate. This agrees well with the experimental finding that, beyond <i>N</i> = 24 the single polyglutamine chain is the critical nucleus for the aggregation of amyloid fibrils. A finite size scaling of the ordering temperatures reveals that for this chain length (and longer chains) folding occurs at physiological (respectively larger) temperatures, whereas shorter chains are disordered at physiological conditions.</p>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 5","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202200075","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44370061","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":"Brownian Dynamics Investigations of the Scattering Functions of Ideal and Excluded Volume Linear Polymers in Higher Dimensions","authors":"Khoa Dang Dinh, Marvin Bishop","doi":"10.1002/mats.202300024","DOIUrl":"10.1002/mats.202300024","url":null,"abstract":"<p>Brownian Dynamics is used to investigate the scattering functions of ideal and excluded volume linear polymers in two to seven spatial dimensions. The scattering functions for ideal and excluded volume polymers examined are in agreement with theoretical predictions in all dimensions. As the dimension is increased, the scattering functions for the excluded volume chains converge toward the ideal results. These findings indicate that excluded volume chains behave more and more as ideal ones as the dimension gets larger.</p>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 5","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48575350","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":"Emergence and Stability of Hierarchical Structures under Cylindrical Confinement","authors":"Tiancheng Chen, Yuci Xu","doi":"10.1002/mats.202370005","DOIUrl":"https://doi.org/10.1002/mats.202370005","url":null,"abstract":"<p><b>Front Cover</b>: In article number 2200076, Tiancheng Chen and Yuci Xu study the self-assembly of A(BC)<sub>2</sub>B multiblock copolymer in a nanopore using the self-consistent field theory. Obtain the hierarchical concentric ring (HC<sub><i>k</i></sub>), hierarchical perforated cylinder (HP<sub><i>k</i></sub>), hierarchical helix (HH<sub><i>k</i></sub>), and hierarchical disk (HD<sub><i>k</i></sub>) in research. Then discuss the stability of hierarchical structures by exploring the influence of pore size and <i>χ</i><sub>AB</sub> on <i>k</i>.\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":"32 3","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202370005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50137174","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. 3/2023","authors":"","doi":"10.1002/mats.202370006","DOIUrl":"https://doi.org/10.1002/mats.202370006","url":null,"abstract":"","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 3","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202370006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50137175","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":"Coalescence of Sessile Polymer Droplets: A Molecular Dynamics Study","authors":"Soheil Arbabi, Panagiotis E. Theodorakis","doi":"10.1002/mats.202300017","DOIUrl":"10.1002/mats.202300017","url":null,"abstract":"<p>Droplet coalescence is ubiquitous in nature and, at the same time key to various technologies, such as inkjet printing. Herein, this study reports on the coalescence of polymer droplets with different chain lengths coalescing on substrates of different wettability. By means of molecular dynamics simulations of a coarse-grained model, it is found that the rate of bridge growth is higher in the case of droplets with smaller contact angles (more wettable substrates) and decreases with the increase of the chain length of the polymers. Different behavior is also identified in the dynamics of the approach of the two droplets during coalescence with the substrate wettability playing a more important role compared to the chain length of the polymers. While the dynamics of the droplet are greatly affected by the latter parameters, the density profile and flow patterns remain the same for the different cases. Thus, this study anticipates that it provides further insights into the coalescence of liquid polymer droplets on solid substrates with implications for relevant technologies.</p>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 5","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44222983","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":"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":"<p>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 (<i>J</i>) cycles of dissociation and reassociation. After finally separating, one of these stickers finds a new open partner in time τ<sub>open</sub> via a subdiffusive process whose mean-squared displacement is proportional to <i>t</i><sup>α</sup>, where <i>t</i> is the time elapsed, and α is the subdiffusion exponent. The RBLM makes convenient mathematical approximations to obtain analytical expressions for <i>J</i> and τ<sub>open</sub>. 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 τ<sub>open</sub> and <i>J</i>, especially at lower values of α. For α = 0.5, corresponding to the Rouse limit, it is found that τ<sub>open</sub> is overestimated by a factor of approximately 4x, while the approximation for <i>J</i> 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.</p>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 4","pages":""},"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}
{"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":"<p>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.</p>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 5","pages":""},"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}