Polymerization Kinetics of Microgel Particles

Elaı̈ssari, Abdelhamid; Mahdavian, Ali Reza

doi:10.1002/9783527632992.ch2

Cited by 2 publications

(2 citation statements)

References 66 publications

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“…Other components, such as surfactants, are often added to obtain particles with small sizes . Other parameters, such as the initiator concentration, may influence the synthesis and the final density profile in ways that are not fully understood yet. , Therefore, we stress that in our approach we do not aim to reproduce the experimental protocol for the synthesis in its different aspects, but rather to adjust the several involved parameters, such as the confinement but also the patchy potential between different species, in order to achieve network realizations that are as similar as possible to the experimental particles in their basic properties, such as swelling behavior and elastic properties. The latter will be addressed in future work.…”

Section: Methodsmentioning

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: Methodsmentioning

confidence: 99%

In Silico Synthesis of Microgel Particles

et al. 2017

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“…Perhaps the cross-linker does not have enough time to diffuse uniformly through the volume during synthesis, leading to large and highly polydisperse polymer clusters and a significant amount of un-cross-linked polymer chains. It is also possible that the change of T syn alters the relative HPC collapse and DVS cross-linking kinetics 48 during the synthesis, resulting in particles that are formed when chains are cross-linked in varying degrees of collapse and/or aggregation.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Effect of Synthesis Temperature on Size, Structure, and Volume Phase Transition of Polysaccharide Microgels

2020

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High-molecular-weight polysaccharide microgels were synthesized at a range of temperatures above the polymer lower critical solution temperature (LCST) (ΔT = 0.6–18.1 °C), and ΔT was found to strongly influence the structure, dynamics, and volume phase transition temperature of the resulting particles. Static and dynamic light scattering studies and mean field theory analysis of the microgels below and above volume phase transition revealed several distinct regimes. At small ΔT, lower density, larger, and more polydisperse microgels that deswell by a factor 10 in volume were synthesized. At intermediate ΔT = 5–8 °C, the formed microgels were the smallest, densest, and most monodisperse below the transition, but exhibited deswelling only by a factor of 5 above the transition. Synthesis at high ΔT led to the formation of nonuniform microgels with small density, a high degree of polydispersity, and in some cases the apparent presence of the un-cross-linked polymer. Furthermore, the volume phase transition temperature dropped significantly as ΔT increased. This work suggests that synthesis temperature can be used to tune the size, deswelling capacity, and volume phase transition temperature of the polymeric microgels.

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Polymerization Kinetics of Microgel Particles

Cited by 2 publications

References 66 publications

In Silico Synthesis of Microgel Particles

In Silico Synthesis of Microgel Particles

Effect of Synthesis Temperature on Size, Structure, and Volume Phase Transition of Polysaccharide Microgels

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