Polymer Conformations in Ionic Microgels in the Presence of Salt: Theoretical and Mesoscale Simulation Results

Kobayashi, Hideki; Halver, René; Sutmann, Godehard; Winkler, Roland G.

doi:10.3390/polym9010015

Cited by 47 publications

(34 citation statements)

References 49 publications

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“…By contrast, previous numerical efforts in microgel modeling have focused on unrealistic networks formed by chains of the same length, often connecting cross-linkers placed on crystalline lattice sites. 31−36 A notable exception is provided in refs (37 and 38), where closed polymer networks are constructed by directly joining randomly distributed cross-linkers with polymer chains.…”

Section: Introductionmentioning

confidence: 99%

In Silico Synthesis of Microgel Particles

et al. 2017

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Microgels are colloidal-scale particles individually made of cross-linked polymer networks that can swell and deswell in response to external stimuli, such as changes to temperature or pH. Despite a large amount of experimental activities on microgels, a proper theoretical description based on individual particle properties is still missing due to the complexity of the particles. To go one step further, here we propose a novel methodology to assemble realistic microgel particles in silico. We exploit the self-assembly of a binary mixture composed of tetravalent (cross-linkers) and bivalent (monomer beads) patchy particles under spherical confinement in order to produce fully bonded networks. The resulting structure is then used to generate the initial microgel configuration, which is subsequently simulated with a bead–spring model complemented by a temperature-induced hydrophobic attraction. To validate our assembly protocol, we focus on a small microgel test case and show that we can reproduce the experimental swelling curve by appropriately tuning the confining sphere radius, something that would not be possible with less sophisticated assembly methodologies, e.g., in the case of networks generated from an underlying crystal structure. We further investigate the structure (in reciprocal and real space) and the swelling curves of microgels as a function of temperature, finding that our results are well described by the widely used fuzzy sphere model. This is a first step toward a realistic modeling of microgel particles, which will pave the way for a careful assessment of their elastic properties and effective interactions.

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Section: Introductionmentioning

confidence: 99%

In Silico Synthesis of Microgel Particles

et al. 2017

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“…This work can help shed light onto the behavior of weak nanogels, which are purely polymeric. Simulations of nanogels have been performed mainly on strongly-charged gels [8,12,13,14,15,16,17,18].…”

Section: Introductionmentioning

confidence: 99%

Computer Simulations of Static and Dynamical Properties of Weak Polyelectrolyte Nanogels in Salty Solutions

Sibrac

Landsgesell

Holm

2017

Gels

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We investigate the chemical equilibria of weak polyelectrolyte nanogels with reaction ensemble Monte Carlo simulations. With this method, the chemical identity of the nanogel monomers can change between neutral or charged following the acid-base equilibrium reaction HA ⇌ A− + H+. We investigate the effect of changing the chemical equilibria by modifying the dissociation constant Knormala. These simulations allow for the extraction of static properties like swelling equilibria and the way in which charge—both monomer and ionic—is distributed inside the nanogel. Our findings reveal that, depending on the value of Knormala, added salt can either increase or decrease the gel size. Using the calculated mean-charge configurations of the nanogel from the reaction ensemble simulation as a quenched input to coupled lattice-Boltzmann molecular dynamics simulations, we investigate dynamical nanogel properties such as the electrophoretic mobility μ and the diffusion coefficient D.

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“…The importance of micro-and nanogels stimulated the application of many different approaches, experimental and theoretical, to study their structural, mechanical, and rheological properties [48][49][50][51][52][53][54][55][56][57][58][59][60]. In particular, computer simulations on these systems have experienced an important development in very recent years with the adoption of a more realistic representation of the polymer network, moving away from the lattice or regular structures used in former models [57,61,62].…”

Section: Introductionmentioning

confidence: 99%

The influence of an applied magnetic field on the self-assembly of magnetic nanogels

Novikau

Sánchez

Kantorovich

2020

Journal of Molecular Liquids

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Using Langevin dynamics simulations, we investigate the self-assembly of magnetic nanogels in the presence of applied magnetic fields of moderate strength. We find that even weak fields lead to drastic changes in the structure factors of both, the embedded magnetic nanoparticles and of whole nanogel particles. Nanogels assemble by uniting magnetic particle clusters forming inter-gel bridges. At zero field the average amount of such bridges for a pair of nanogels is close to one, whereas even for weak fields it fastly doubles. Rapid growth of cluster size at low values of the applied field is followed by a broad region of slow increase, caused by the mechanical constraints imposed the polymer matrix. The influence of the latter manifests itself in both, the slow growth of the magnetisation curve at intermediate fields and the slow decay of the total Zeeman energy.

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Polymer Conformations in Ionic Microgels in the Presence of Salt: Theoretical and Mesoscale Simulation Results

Cited by 47 publications

References 49 publications

In Silico Synthesis of Microgel Particles

In Silico Synthesis of Microgel Particles

Computer Simulations of Static and Dynamical Properties of Weak Polyelectrolyte Nanogels in Salty Solutions

The influence of an applied magnetic field on the self-assembly of magnetic nanogels

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