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Staňo R, Košovan P, Tagliabue A, Holm C. Electrostatically Cross-Linked Reversible Gels—Effects of pH and Ionic Strength. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00470] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Roman Staňo
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Prague, Czech Republic
| | - Peter Košovan
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Prague, Czech Republic
| | - Andrea Tagliabue
- Dipartimento di Scienza ed Alta Tecnologia, Universitá degli Studi dell’Insubria, via Valleggio 9, 22100 Como, Italy
| | - Christian Holm
- Institute for Computational Physics, University of Stuttgart, D-70569 Stuttgart, Germany
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Bačová P, Mintis DG, Gkolfi E, Harmandaris V. Mikto-Arm Stars as Soft-Patchy Particles: From Building Blocks to Mesoscopic Structures. Polymers (Basel) 2021; 13:1114. [PMID: 33915849 PMCID: PMC8037958 DOI: 10.3390/polym13071114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/26/2021] [Accepted: 03/27/2021] [Indexed: 11/22/2022] Open
Abstract
We present an atomistic molecular dynamics study of self-assembled mikto-arm stars, which resemble patchy-like particles. By increasing the number of stars in the system, we propose a systematic way of examining the mutual orientation of these fully penetrable patchy-like objects. The individual stars maintain their patchy-like morphology when creating a mesoscopic (macromolecular) self-assembled object of more than three stars. The self-assembly of mikto-arm stars does not lead to a deformation of the stars, and their shape remains spherical. We identified characteristic sub-units in the self-assembled structure, differing by the mutual orientation of the nearest neighbor stars. The current work aims to elucidate the possible arrangements of the realistic, fully penetrable patchy particles in polymer matrix and to serve as a model system for further studies of nanostructured materials or all-polymer nanocomposites using the mikto-arm stars as building blocks.
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Affiliation(s)
- Petra Bačová
- Computation-Based Science and Technology Research Center, The Cyprus Institute, 20 Constantinou Kavafi Str., Nicosia 2121, Cyprus; (D.G.M.); (V.H.)
- Institute of Applied and Computational Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), GR-70013 Heraklion, Crete, Greece;
| | - Dimitris G. Mintis
- Computation-Based Science and Technology Research Center, The Cyprus Institute, 20 Constantinou Kavafi Str., Nicosia 2121, Cyprus; (D.G.M.); (V.H.)
| | - Eirini Gkolfi
- Institute of Applied and Computational Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), GR-70013 Heraklion, Crete, Greece;
- Department of Mathematics and Applied Mathematics, University of Crete, GR-70013 Heraklion, Crete, Greece
| | - Vagelis Harmandaris
- Computation-Based Science and Technology Research Center, The Cyprus Institute, 20 Constantinou Kavafi Str., Nicosia 2121, Cyprus; (D.G.M.); (V.H.)
- Institute of Applied and Computational Mathematics (IACM), Foundation for Research and Technology Hellas (FORTH), GR-70013 Heraklion, Crete, Greece;
- Department of Mathematics and Applied Mathematics, University of Crete, GR-70013 Heraklion, Crete, Greece
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Tagliabue A, Landsgesell J, Mella M, Holm C. Can oppositely charged polyelectrolyte stars form a gel? A simulational study. SOFT MATTER 2021; 17:1574-1588. [PMID: 33351002 DOI: 10.1039/d0sm01617a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We present a Langevin molecular dynamics study of an equimolar mixture of monodispersed oppositely charged di-block four-armed polyelectrolyte stars. We used an implicit solvent coarse-grained representation of the polyelectrolyte stars, and varied the length of the terminal charged blocks that reside on each arm. By varying the polymer concentration, we computed PV diagrams and determined the free-swelling equilibrium concentration with respect to a pure water reservoir as a function of the charged block length. We investigated various structural properties of the resulting equilibrium structures, like the number of ionic bonds, dangling arms, isolated stars, and cluster sizes. The ionic bonds featured a broad distribution of the number of arms involved and also displayed a distribution of net charges peaked around the neutral ionic bond. Our main result is that for charged block length equal to 4 and 5 ionized beads the resulting macro-aggregate spans the box and forms a network phase. Furthermore, we investigated the restructuring dynamics of ionic bonds; the results suggested both short bond lifetimes and a high frequency of ballistic association/dissociation events. Bonds result strong enough to yield a stable gel phase, but they are still weak enough to allow network restructuring under thermal fluctuations.
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Affiliation(s)
- Andrea Tagliabue
- Dipartimento di Scienza ed Alta Tecnologia, Università degli Studi dell'Insubria, via Valleggio 9, 22100, Como, Italy
| | - Jonas Landsgesell
- Institute for Computational Physics, University of Stuttgart, Allmandring 3, Stuttgart, 70569, Germany.
| | - Massimo Mella
- Dipartimento di Scienza ed Alta Tecnologia, Università degli Studi dell'Insubria, via Valleggio 9, 22100, Como, Italy
| | - Christian Holm
- Institute for Computational Physics, University of Stuttgart, Allmandring 3, Stuttgart, 70569, Germany.
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Jaramillo-Cano D, Camargo M, Likos CN, Gârlea IC. Dynamical Properties of Concentrated Suspensions of Block Copolymer Stars in Shear Flow. Macromolecules 2020; 53:10015-10027. [PMID: 33335338 PMCID: PMC7735753 DOI: 10.1021/acs.macromol.0c01365] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 10/02/2020] [Indexed: 01/19/2023]
Abstract
Block copolymer stars (BCSs) have been demonstrated to constitute versatile, self-assembling building blocks with tunable softness, functionalization, and shape. We investigate the dynamical properties of suspensions of short-arm BCSs under linear shear flow by means of extensive particle-based multiscale simulations. We determine the properties of the system for representative values of monomer packing fraction ranging from semidilute to concentrate regimes. We systematically analyze the formed network structures as a function of both shear rate and packing fraction, the reorganization of solvophobic patches, and the corresponding radial correlation functions. Connecting our findings with rheology, we calculate the viscosity as a function of shear rate and discuss the implications of the found shear thinning behavior.
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Affiliation(s)
- Diego Jaramillo-Cano
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
| | - Manuel Camargo
- CICBA & FIMEB, Universidad Antonio Nariño, 760030 Cali, Colombia
| | - Christos N. Likos
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
| | - Ioana C. Gârlea
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
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Yang J, Wang R, Xie D. Self-organization in suspensions of telechelic star polymers. POLYMER 2020. [DOI: 10.1016/j.polymer.2020.122866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
AbstractThe self-assembly of Janus ring polymers is studied via a coarse-grained molecular dynamics employing a bead spring model including bending rigidity contributions to the Hamiltonian. We examine the formation and the morphology of amphiphilicity-driven clusters in the system using the number density ρN, the temperature T, the fraction of solvophobic monomers α, and the stiffness of the polymer rings κ as control parameters. We present a quantitative analysis of several characteristics for the formed clusters of Janus rings. Measured quantities include the distribution of the cluster size MC and the shape of the clusters in the form of the prolate/oblate factor Q and shape factors sf. We demonstrate Janus rings form polymorphic micelles that vary from a spherical shape, akin to that known for linear block copolymers, to a novel type of toroidal shape, and we highlight the role played by the key physical parameters leading to the stabilization of such structures.
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Ruiz-Franco J, Jaramillo-Cano D, Camargo M, Likos CN, Zaccarelli E. Multi-particle collision dynamics for a coarse-grained model of soft colloids. J Chem Phys 2019; 151:074902. [PMID: 31438712 DOI: 10.1063/1.5113588] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The growing interest in the dynamical properties of colloidal suspensions, both in equilibrium and under an external drive such as shear or pressure flow, requires the development of accurate methods to correctly include hydrodynamic effects due to the suspension in a solvent. In the present work, we generalize Multiparticle Collision Dynamics (MPCD) to be able to deal with soft, polymeric colloids. Our methods build on the knowledge of the monomer density profile that can be obtained from monomer-resolved simulations without hydrodynamics or from theoretical arguments. We hereby propose two different approaches. The first one simply extends the MPCD method by including in the simulations effective monomers with a given density profile, thus neglecting monomer-monomer interactions. The second one considers the macromolecule as a single penetrable soft colloid (PSC), which is permeated by an inhomogeneous distribution of solvent particles. By defining an appropriate set of rules to control the collision events between the solvent and the soft colloid, both linear and angular momenta are exchanged. We apply these methods to the case of linear chains and star polymers for varying monomer lengths and arm number, respectively, and compare the results for the dynamical properties with those obtained within monomer-resolved simulations. We find that the effective monomer method works well for linear chains, while the PSC method provides very good results for stars. These methods pave the way to extend MPCD treatments to complex macromolecular objects such as microgels or dendrimers and to work with soft colloids at finite concentrations.
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Affiliation(s)
- José Ruiz-Franco
- CNR-ISC, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
| | - Diego Jaramillo-Cano
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
| | - Manuel Camargo
- FIMEB & CICBA, Universidad Antonio Nariño - Campus Farallones, Km 18 vía Cali-Jamundí, 760030 Cali, Colombia
| | - Christos N Likos
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
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