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Kurbatov AO, Balabaev NK, Litvin KA, Kramarenko EY. Structure and Mechanical Response of Polybutylcarbosilane Dendrimers Confined in a Flat Slit: Effect of Molecular Architecture and Generation Number. Polymers (Basel) 2023; 15:4040. [PMID: 37896283 PMCID: PMC10610163 DOI: 10.3390/polym15204040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/05/2023] [Accepted: 10/07/2023] [Indexed: 10/29/2023] Open
Abstract
Due to the absence of specific interactions, carbosilane dendrimers are ideal models to study the effect of a hyperbranched regular structure on the molecular response to external influences. In this work, we have studied the conformational behavior of single polybutylcarbosilane dendrimers under confinement between impermeable flat surfaces using atomistic molecular dynamics simulations. Dendrimers of different generations belonging to two homologous series with a tetra-functional core and three- and four-functional branches were simulated. The analysis of the dependence of the internal energy of the dendrimers on the wall distance allowed us to determine the critical degree of compression at which the dendrimers are able to change their shape without energy loss. The effects of generation number and branching functionality on the number of wall contacts, density distribution and shape changes were elucidated. It was found that for high generation dendrimers, the inner layers are not accessible for external interaction. It was shown that the excess stresses occurring at high compressions are concentrated in the structural center of the dendrimer. The nature of the elastic response, which is strongly nonlinear, was analyzed at different compressions depending on the dendrimer architecture and generation. We believe that our results are useful for further studies of dendrimer films under compression and can also serve as a basis for developing model concepts to describe the dynamics of dendrimer melts.
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Affiliation(s)
- Andrey O. Kurbatov
- Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia; (A.O.K.); (K.A.L.)
- Enikolopov Institute of Synthetic Polymeric Materials RAS, Moscow 119991, Russia
| | - Nikolay K. Balabaev
- Institute of Mathematical Problems of Biology RAS—The Branch of Keldysh Institute of Applied Mathematics of Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russia;
| | - Kirill A. Litvin
- Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia; (A.O.K.); (K.A.L.)
| | - Elena Yu. Kramarenko
- Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia; (A.O.K.); (K.A.L.)
- Enikolopov Institute of Synthetic Polymeric Materials RAS, Moscow 119991, Russia
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Polanowski P, Hałagan K, Sikorski A. Star Polymers vs. Dendrimers: Studies of the Synthesis Based on Computer Simulations. Polymers (Basel) 2022; 14:2522. [PMID: 35808567 PMCID: PMC9269100 DOI: 10.3390/polym14132522] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/18/2022] [Accepted: 06/19/2022] [Indexed: 01/24/2023] Open
Abstract
A generic model was developed for studies of the polymerization process of regular branched macromolecules. Monte Carlo simulations were performed employing the Dynamic Lattice Liquid algorithm to study this process. A core-first methodology was used in a living polymerization of stars with up to 32 arms, and dendrimers consisted of 4-functional segments. The kinetics of the synthesis process for stars with different numbers of branches and dendrimers was compared. The size and structure of star-branched polymers and dendrimers during the synthesis were studied. The influence of the functionality of well-defined cores on the structure and on the dispersity of the system was also examined. The differences in the kinetics in the formation of both architectures, as well as changes to their structures, were described and discussed.
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Affiliation(s)
- Piotr Polanowski
- Department of Molecular Physics, Lodz University of Technology, 90-924 Lodz, Poland; (P.P.); (K.H.)
| | - Krzysztof Hałagan
- Department of Molecular Physics, Lodz University of Technology, 90-924 Lodz, Poland; (P.P.); (K.H.)
| | - Andrzej Sikorski
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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Markelov DA, Semisalova AS, Mazo MA. Formation of a Hollow Core in Dendrimers in Solvents. MACROMOL CHEM PHYS 2021. [DOI: 10.1002/macp.202100085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Denis A. Markelov
- Saint Petersburg State University Universitetskaya nab. 7/9 St. Petersburg 199034 Russia
| | - Anna S. Semisalova
- Faculty of Physics and CENIDE University of Duisburg‐Essen Lotharstr. 1 Duisburg 47057 Germany
| | - Mikhail A. Mazo
- Semenov Institute of Chemical Physics Russian Academy of Sciences Kosygina 4 Moscow 119991 Russia
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Katarzhnova EY, Tatarinova EA, Ignat’eva GM, Vasilenko NG, Meshkov IB, Muzafarov AM. New sparse polymethylsiloxane dendrimers. MENDELEEV COMMUNICATIONS 2021. [DOI: 10.1016/j.mencom.2021.04.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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New sparse polymethylsiloxane dendrimers. MENDELEEV COMMUNICATIONS 2021. [DOI: 10.1016/j.mencom.2021.05.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Kurbatov AO, Balabaev NK, Mazo MA, Kramarenko EY. Adsorption of Silicon-Containing Dendrimers: Effects of Chemical Composition, Structure, and Generation Number. Polymers (Basel) 2021; 13:552. [PMID: 33668463 PMCID: PMC7917902 DOI: 10.3390/polym13040552] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/07/2021] [Accepted: 02/11/2021] [Indexed: 11/17/2022] Open
Abstract
We studied the conformational behavior of silicon-containing dendrimers during their adsorption onto a flat impenetrable surface by molecular dynamics (MD) simulations. Four homologous series of dendrimers from the 4th up to the 7th generations were modeled, namely, two types of carbosilane dendrimers differing by the functionality of the core Si atom and two types of siloxane dendrimers with different lengths of the spacers. Comparative analysis of the fractions of adsorbed atoms belonging to various structural layers within dendrimers as well as density profiles allowed us to elucidate not only some general trends but also the effects determined by dendrimer specificity. In particular, it was found that in contrast to the carbosilane dendrimers interacting with the adsorbing surface mainly by their peripheral layers, the siloxane dendrimers with the longer -O-Si(CH3)2-O spacers expose atoms from their interior to the surface spreading out on it. These findings are important for the design of functional materials on the basis of silicon-containing dendrimers.
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Affiliation(s)
- Andrey O. Kurbatov
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia;
- A. N. Nesmeyanov Institute of Organoelement Compounds RAS, 119991 Moscow, Russia
| | - Nikolay K. Balabaev
- Institute of Mathematical Problems of Biology, Keldysh Institute of Applied Mathematics RAS, Pushchino, 142290 Moscow, Russia;
| | - Mikhail A. Mazo
- Semenov Institute of Chemical Physics RAS, 119991 Moscow, Russia;
| | - Elena Yu. Kramarenko
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia;
- A. N. Nesmeyanov Institute of Organoelement Compounds RAS, 119991 Moscow, Russia
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Boldyrev K, Chernyak A, Meshkov I, Muzafarov A, Tatarinova E, Vasil'ev S. The self-diffusion of polymethylsilsesquioxane (PMSSO) dendrimers in diluted solutions and melts. SOFT MATTER 2020; 16:9712-9725. [PMID: 32996536 DOI: 10.1039/d0sm01183e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Recently developed non-functional derivatives of polymethylsilsesquioxane (PMSSO) dendrimers of the first to fifth generation were characterized by 1H, 13C and 29Si NMR spectroscopy. The self-diffusion and NMR relaxation of PMSSO dendrimers in dilute solutions of toluene and melts were investigated in a wide temperature range (-50-80 °C). The hydrodynamic radii of dendrimers were determined from the self-diffusion coefficients measured in diluted solutions according to the Stokes-Einstein equation. The hydrodynamic radius of PMSSO dendrimers as a function of molecular mass follows a power law with the scaling exponent of 0.32 ± 0.02 in the investigated temperature range. The temperature dependences of the self-diffusion coefficients of dendrimers were described by the Arrhenius-type equation. The activation energies of self-diffusion of dendrimers in diluted toluene solutions are identical for different generations while the dependence of activation energy for dendrimers in melts shows a maximum for the third generation (G3) dendrimer. Taking into account the absence of specific interactions in PMSSO dendrimer melts the observed behavior was ascribed to the manifestation of interpenetration of dendrimer molecules. For low generations (G1 and G2) the short length of the branches does not considerably affect the translational diffusion while for higher generations (G4 and G5) the densification of the structure prevents significant interpenetration.
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Affiliation(s)
- Konstantin Boldyrev
- N.S. Enikolopov Institute of Synthetic Polymeric Materials of Russian Academy of Sciences, Profsoyuznaya st. 70, 117393 Moscow, Russia
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Kurbatov AO, Balabaev NK, Mazo MA, Kramarenko EY. Effects of generation number, spacer length and temperature on the structure and intramolecular dynamics of siloxane dendrimer melts: molecular dynamics simulations. SOFT MATTER 2020; 16:3792-3805. [PMID: 32239060 DOI: 10.1039/d0sm00095g] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The structure and properties of polysiloxane dendrimer melts are studied by extensive atomistic molecular dynamics simulations. Two homologous series differing in the spacer length are considered. In the first series the dendrimer spacers are the shortest ones, comprising only one oxygen atom, while in the second series the spacers consist of two oxygen atoms with the silicon atom in between. Melts of the dendrimers from the 3rd up to the 6th generation number are modelled in a wide temperature range from 273 to 600 K. A comparative study of the macroscopic melt characteristics such as the melt density and thermal expansion coefficients is performed for the two series. Analysis of the dendrimer structure in melts and in the isolated state shows that intermolecular interactions and interpenetration of dendrimer molecules in melts hardly affect the dendrimer interior organization. However, the presence of neighboring molecules significantly slows down their intramolecular dynamics in melts in comparison with that of isolated dendrimers. An increasing generation number causes an increase of the radius of the dendrimer interior region unavailable for neighboring molecules, which starts to exceed the length of the peripheral interpenetration layer for high-generation dendrimers; this fact could lead to different mechanisms of melt dynamics for lower and higher generation dendrimers.
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Affiliation(s)
- Andrey O Kurbatov
- Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia. and A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Moscow 119991, Russia
| | - Nikolay K Balabaev
- Institute of Mathematical Problems of Biology, Keldysh Institute of Applied Mathematics RAS, Pushchino, Moscow 142290, Russia
| | - Mikhail A Mazo
- Semenov Institute of Chemical Physics RAS, Moscow 119991, Russia
| | - Elena Yu Kramarenko
- Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia. and A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Moscow 119991, Russia
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Molecular Insights into Sequence Distributions and Conformation-Dependent Properties of High-Phenyl Polysiloxanes. Polymers (Basel) 2019; 11:polym11121989. [PMID: 31810258 PMCID: PMC6960887 DOI: 10.3390/polym11121989] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 11/23/2019] [Accepted: 11/24/2019] [Indexed: 11/17/2022] Open
Abstract
The excellent performance and wide applications of phenyl polysiloxanes are largely due to their phenyl units and monomer sequences. However, the relationship between molecular structure and material properties has not been explicitly elucidated. In this work, the sequence distribution and microstructure of random copolymers were quantitatively investigated by means of a molecular dynamics (MD) simulation combined with experimental verification. The results of 29Si NMR showed that the large number of phenyl units not only shortened the length of the dimethyl units, but also significantly increased the proportion of consecutive phenyl units. The simulation results indicated the attraction between adjacent phenyl groups that were effectively strengthened intra- and inter- molecular interactions, which determined the equilibrium population of conformations and the dynamics of conformational transitions. Furthermore, the evolution of bond angle distribution, torsion distribution, and mean-squared displacements (MSD) shed light on the conformational characteristics that induce the unique thermodynamics properties and photophysical behavior of high-phenyl polysiloxanes. Differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA), spectrofluorimetry, and laser scanning confocal microscopy (LSCM) were performed to verify the conclusions drawn from the simulation. Overall, the complementary use of MD simulations and experiments provided a deep molecular insight into structure-property relationships, which will provide theoretical guidance for the rational design and preparation of high-performance siloxanes.
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Kondratyuk N. Contributions of force field interaction forms to Green-Kubo viscosity integral in n-alkane case. J Chem Phys 2019; 151:074502. [PMID: 31438709 DOI: 10.1063/1.5103265] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Decades of molecular simulation history proved that the Green-Kubo method for shear viscosity converges without any problems in atomic and simple molecular liquids, unlike liquids with high values of viscosity. In the case of highly viscous liquids, the time decomposition method was developed in 2015 by Maginn and co-authors [Y. Zhang, A. Otani, and E. J. Maginn, J. Chem. Theory Comput. 11, 3537-3546 (2015)] which allows us to improve the convergence of the Green-Kubo integral. In this paper, the contributions of intramolecular and intermolecular force field parts to the viscosity integral are discovered to gain the understanding of the Green-Kubo method. The n-alkanes from n-ethane to n-pentane at 330 K in the optimized potentials for liquid simulations-all atom force field are used as reference models. The dependencies of these contributions and decay times of the corresponding correlation functions on the chain length are observed. The nonequilibrium simulations are carried out to verify the Green-Kubo results. The obtained values of viscosity are compared with experimental data.
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Affiliation(s)
- N Kondratyuk
- Moscow Institute of Physics and Technology (National Research University), 141700 Dolgoprudnyi, Russia and Joint Institute for High Temperatures of the Russian Academy of Sciences, 125412 Moscow, Russia
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Kurbatov AO, Balabaev NK, Mazo MA, Kramarenko EY. A Comparative Study of Intramolecular Mobility of Single Siloxane and Carbosilane Dendrimers via Molecular Dynamics Simulations. Polymers (Basel) 2018; 10:E838. [PMID: 30960763 PMCID: PMC6403907 DOI: 10.3390/polym10080838] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 07/26/2018] [Accepted: 07/27/2018] [Indexed: 01/27/2023] Open
Abstract
A comparative analysis of intramolecular dynamics of four types of isolated dendrimers from the fourth to the seventh generations belonging to the siloxane and carbosilane families, differing in spacer length, core functionality, and the type of chemical bonds, has been performed via atomic molecular dynamics simulations. The average radial and angular positions of all Si branching atoms of various topological layers within the dendrimer interior, as well as their variations, have been calculated, and the distributions of the relaxation times of their radial and angular motions have been found. It has been shown that the dendrons of all the dendrimers elongate from the center and decrease in a solid angle with an increasing generation number. The characteristic relaxation times of both angular and radial motions of Si atoms are of the order of a few nanoseconds, and they increase with an increasing generation number and decrease with temperature, with the angular relaxation times being larger than the radial ones. The relaxation times in the carbosilanes are larger than those in the siloxanes. The rotational angle dynamics of the carbosilane dendrimers show that the chain bending is mainly realized via trans-gauche transitions in the Si branching bonds.
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Affiliation(s)
- Andrey O Kurbatov
- Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia.
- A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Moscow 119991, Russia.
| | - Nikolay K Balabaev
- Institute of Mathematical Problems of Biology, Keldysh Institute of Applied Mathematics RAS, Pushchino, Moscow 142290, Russia.
| | - Mikhail A Mazo
- Semenov Institute of Chemical Physics RAS, Moscow 119991, Russia.
| | - Elena Yu Kramarenko
- Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia.
- A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Moscow 119991, Russia.
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