<i>In Silico</i> Synthesis of Microgel Particles

Gnan, Nicoletta; Rovigatti, Lorenzo; Bergman, Maxime J.; Zaccarelli, Emanuela

doi:10.1021/acs.macromol.7b01600

Cited by 125 publications

(246 citation statements)

References 65 publications

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“…In the low-temperature limit, swaps are required to reach true equilibrium configurations (75), hence we keep ∆Eswap = 0 during equilibration. The inclusion of swap events also accelerates the process of initial self-assembly (76).…”

Section: R a F Tmentioning

confidence: 99%

Understanding, predicting, and tuning the fragility of vitrimeric polymers

Ciarella

Biezemans

Janssen

2019

Proc. Natl. Acad. Sci. U.S.A.

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Fragility is an empirical property that describes how abruptly a glassforming material solidifies upon supercooling. The degree of fragility carries important implications for the functionality and processability of a material, as well as for our fundamental understanding of the glass transition. However, the microstructural properties underlying fragility still remain poorly understood. Here, we explain the microstructure-fragility link in vitrimeric networks, a novel type of high-performance polymers with unique bond-swapping functionality and unusual glass-forming behavior. Our results are gained from coarse-grained computer simulations and first-principles Mode-Coupling Theory (MCT) of star-polymer vitrimers. We first demonstrate that the vitrimer fragility can be tuned over an unprecedentedly broad range, from fragile to strong and even superstrong behavior, by decreasing the bulk density. Remarkably, this entire phenomenology can be reproduced by microscopic MCT, thus challenging the conventional belief that existing first-principles theories cannot account for non-fragile behaviors. Our MCT analysis allows us to rationally identify the microstructural origin of the fragile-tosuperstrong crossover, which is rooted in the sensitivity of the static structure factor to temperature variations. On the molecular scale, this behavior stems from a change in dominant length scales, switching from repulsive excluded-volume interactions to intrachain attractions as the vitrimer density decreases. Finally, we develop a simplified schematic MCT model which corroborates our microscopically-founded conclusions and which unites our findings with earlier MCT studies. Our work sheds new light on the elusive structure-fragility link in glass-forming matter, and provides a firstprinciples-based platform for designing novel amorphous materials with an on-demand dynamic response.Keyword 1 | Keyword 2 | Keyword 3 | ... Significance StatementThe intricate interplay between the molecular structure of a material and its emergent macroscopic dynamics lies at the heart of modern materials science. This interplay, however, remains notoriously poorly understood for glass-forming systems. The recent advent of vitrimers-a promising new class of recyclable high-performance polymers with anomalous glassforming properties -revives the urgency to gain a full understanding of the elusive structure-dynamics link in glassy matter. We combine computer simulations and first-principles theory to rationally expose the structural origins of the complex glassy dynamics in vitrimers. Our findings provide cues for a better fundamental understanding of glass formation, and may stimulate the development of novel, sustainable amorphous materials with on-demand functionalities.

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Section: R a F Tmentioning

confidence: 99%

Understanding, predicting, and tuning the fragility of vitrimeric polymers

Ciarella

Biezemans

Janssen

2019

Proc. Natl. Acad. Sci. U.S.A.

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“…This confirms that the numerical techniques that we have introduced in this work could be a first step to investigate the hydrodynamics of complex macromolecules that cannot be attained with MRM simulations. It is our intention to apply this approach to the study of other polymeric systems, such as microgels, 42,43 for which accurate monomer density profiles have recently been calculated at different solvophobic conditions. 44 Furthermore, this method opens up the possibility to go beyond single-particle studies and to address the dynamics of polymeric objects at finite concentrations.…”

Section: Discussionmentioning

confidence: 99%

Multi-particle collision dynamics for a coarse-grained model of soft colloids

Ruiz-Franco

Jaramillo-Cano

Camargo

et al. 2019

The Journal of Chemical Physics

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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 Multi-Particle 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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“…All the non-bonded interactions were implemented by a, purely repulsive, Weeks-Chandler-Andersen (WCA) potential [25] that was modified in order to tune the quality of the solvent. This was achieved by introducing an attractive tail, regulated by a solvent quality parameter φ that sets the solvophobicity of the monomers [23,[26][27][28]. Therefore this parameter plays the role of an effective temperature in the model.…”

Section: Model and Simulation Detailsmentioning

confidence: 99%

Coarsening Kinetics of Complex Macromolecular Architectures in Bad Solvent

Paciolla

Arismendi‐Arrieta²,

Moreno

2019

Preprint

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This study reports a general scenario for the out-of-equilibrium features of collapsing polymeric architectures. We use molecular dynamics simulations to characterize the coarsening kinetics, in bad solvent, for several macromolecular systems with an increasing degree of structural complexity. In particular, we focus on: flexible and semiflexible polymer chains, star polymers with 3 and 12 arms, and microgels with both ordered and disordered networks.Starting from a powerful analogy with critical phenomena, we construct a density field representation that removes fast fluctuations and provides a consistent characterization of the domain growth. Our results indicate that the coarsening kinetics presents a scaling behaviour that is independent of the solvent quality parameter, in analogy to time-temperature superposition principle. Interestingly, the domain growth in time follows a power-law behaviour that is approximately independent of the architecture for all the flexible systems; while it is steeper for the semiflexible chains. Nevertheless, the fractal nature of the dense regions emerging during the collapse exhibits the same scaling behaviour for all the macromolecules.This suggests that the faster growing length scale in the semiflexible chains originates just from a faster mass diffusion along the chain contour, induced by the local stiffness. The decay of the dynamic correlations displays scaling behavior with the growing length scale of the system, which is a characteristic signature in coarsening phenomena. I. INTRODUCTIONUnderstanding the collapse of, fully polymeric, topologically complex objects in a bad solvent is of broad importance, because of its relevance in the early stages of the protein folding [1,2], and its connections with arresting processes or aging phenomena [3,4]. The thermodynamic and structural properties of the macromolecular collapse in solution, occurring when the quality of the solvent is decreased below a critical value, have been exhaustively investigated over the years [5][6][7][8][9][10], and at equilibrium, the dynamic and static behavior are well known above and below the volume phase transition [11]. Comparatively, a general framework for the non-equilibrium aspects, as the kinetics of the collapse, is still lacking. The development of new experimental setups for small angle X-ray scattering or single-molecule fluorescence spectroscopy allows to monitor the collapse arXiv:1912.03551v1 [cond-mat.soft]

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In Silico Synthesis of Microgel Particles

Cited by 125 publications

References 65 publications

Understanding, predicting, and tuning the fragility of vitrimeric polymers

Understanding, predicting, and tuning the fragility of vitrimeric polymers

Multi-particle collision dynamics for a coarse-grained model of soft colloids

Coarsening Kinetics of Complex Macromolecular Architectures in Bad Solvent

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