scholarly journals Polyelectrolyte-Nanoplatelet Complexation: Is It Possible to Predict the State Diagram?

2019 ◽  
Vol 20 (24) ◽  
pp. 6217
Author(s):  
Maria Jansson ◽  
Marie Skepö

The addition of polyelectrolytes (PEs) to suspensions of charged colloids, such as nanoplatelets (NPs), is of great interest due to their specific feature of being either a stabilizing or a destabilizing agent. Here, the complexation between a PE and oppositely charged NPs is studied utilizing coarse-grained molecular dynamics simulations based on the continuum model. The complex formation is evaluated with respect to the stoichiometric charge-ratio within the system, as well as by the alternation of the chain properties. It is found that the formed complexes can possess either an extended or a compact shape. Moreover, it is observed that the chain can become overcharged by the oppositely charged NPs. With an increase in chain length, or a decrease in chain flexibility, the complex obtains a more extended shape, where the NPs are less tightly bound to the PE. The latter is also true when reducing the total charge of the chain by varying the linear charge density, whereas in this case, the chain contracts. With our coarse-grained model and molecular dynamics simulations, we are able to predict the composition and the shape of the formed complex and how it is affected by the characteristics of the chain. The take-home message is that the complexation between PEs and NPs results in a versatile and rich state diagram, which indeed is difficult to predict, and dependent on the properties of the chain and the model used. Thus, we propose that the present model can be a useful tool to achieve an understanding of the PE-NPs complexation, a system commonly used in industrial and in technological processes.

Soft Matter ◽  
2019 ◽  
Vol 15 (27) ◽  
pp. 5431-5442 ◽  
Author(s):  
Vaidyanathan Sethuraman ◽  
Michael McGovern ◽  
David C. Morse ◽  
Kevin D. Dorfman

The influence of backbone charge sequence in oppositely charged polyelectrolyte brushes upon their adsorption efficacy is reported at low salt concentration using coarse-grained molecular dynamics simulations.


Soft Matter ◽  
2018 ◽  
Vol 14 (24) ◽  
pp. 5106-5120 ◽  
Author(s):  
Thiago Colla ◽  
Ronald Blaak ◽  
Christos N. Likos

Using molecular dynamics simulations, we investigate the self-assembly of a coarse-grained binary system of oppositely charged microgels, symmetric in size and concentration.


2020 ◽  
Author(s):  
Florencia Klein ◽  
Daniela Cáceres-Rojas ◽  
Monica Carrasco ◽  
Juan Carlos Tapia ◽  
Julio Caballero ◽  
...  

<p>Although molecular dynamics simulations allow for the study of interactions among virtually all biomolecular entities, metal ions still pose significant challenges to achieve an accurate structural and dynamical description of many biological assemblies. This is particularly the case for coarse-grained (CG) models. Although the reduced computational cost of CG methods often makes them the technique of choice for the study of large biomolecular systems, the parameterization of metal ions is still very crude or simply not available for the vast majority of CG- force fields. Here, we show that incorporating statistical data retrieved from the Protein Data Bank (PDB) to set specific Lennard-Jones interactions can produce structurally accurate CG molecular dynamics simulations. Using this simple approach, we provide a set of interaction parameters for Calcium, Magnesium, and Zinc ions, which cover more than 80% of the metal-bound structures reported on the PDB. Simulations performed using the SIRAH force field on several proteins and DNA systems show that using the present approach it is possible to obtain non-bonded interaction parameters that obviate the use of topological constraints. </p>


Author(s):  
Łukasz Piotr Baran ◽  
Wojciech Rżysko ◽  
Dariusz Tarasewicz

In this study we have performed extensive coarse-grained molecular dynamics simulations of the self-assembly of tetra-substituted molecules. We have found that such molecules are able to form a variety of...


2020 ◽  
Vol 22 (16) ◽  
pp. 8757-8767
Author(s):  
Tomasz Staszewski ◽  
Małgorzata Borówko

We use coarse-grained molecular dynamics simulations to study the behavior of polymer-tethered particles immersed in fluids of isotropic particles.


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