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- ItemMolecular structure of bottlebrush polymers in melts(Washington, DC [u.a.] : Assoc., 2016) Paturej, Jarosław; Sheiko, Sergei S.; Panyukov, Sergey; Rubinstein, MichaelBottlebrushes are fascinating macromolecules that display an intriguing combination of molecular and particulate features having vital implications in both living and synthetic systems, such as cartilage and ultrasoft elastomers. However, the progress in practical applications is impeded by the lack of knowledge about the hierarchic organization of both individual bottlebrushes and their assemblies. We delineate fundamental correlations between molecular architecture, mesoscopic conformation, and macroscopic properties of polymer melts. Numerical simulations corroborate theoretical predictions for the effect of grafting density and side-chain length on the dimensions and rigidity of bottlebrushes, which effectively behave as a melt of flexible filaments. These findings provide quantitative guidelines for the design of novel materials that allow architectural tuning of their properties in a broad range without changing chemical composition.
- ItemUniversal size ratios of Gaussian polymers with complex architecture: radius of gyration vs hydrodynamic radius([London] : Macmillan Publishers Limited, part of Springer Nature, 2020) Haydukivska, Khristine; Blavatska, Viktoria; Paturej, JarosławWe study the impact of arm architecture of polymers with a single branch point on their structure in solvents. Many physical properties of polymer liquids strongly dependent on the size and shape measures of individual macromolecules, which in turn are determined by their topology. Here, we use combination of analytical theory, based on path integration method, and molecular dynamics simulations to study structural properties of complex Gaussian polymers containing fc linear branches and fr closed loops grafted to the central core. We determine size measures such as the gyration radius Rg and the hydrodynamic radii RH, and obtain the estimates for the size ratio Rg/RH with its dependence on the functionality f=fc+fr of grafted polymers. In particular, we obtain the quantitative estimate of the degree of compactification of these polymers with increasing number of closed loops fr as compared to linear or star-shape molecules of the same total molecular weight. Numerical simulations corroborate theoretical prediction that Rg/RH decreases towards unity with increasing f. These findings provide qualitative description of polymers with complex architecture in θ solvents.