Molecular Dynamics Simulations of the Interfacial Region between Boehmite and Gibbsite Basal Surfaces and High Ionic Strength Aqueous Solutions

2017 ◽  
Vol 121 (25) ◽  
pp. 13692-13700 ◽  
Author(s):  
Zhizhang Shen ◽  
Eugene S. Ilton ◽  
Micah P. Prange ◽  
Sebastien N. Kerisit
Keyword(s):  
Molecular Dynamics ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Molecular Dynamics Simulations ◽  
High Ionic Strength ◽  
Interfacial Region ◽  
Dynamics Simulations

UNDERSTANDING DIFFERENT LCST LEVELS OF POLY(N-ALKYLACRYLAMIDE)S BY MOLECULAR DYNAMICS SIMULATIONS AND QUANTUM MECHANICS CALCULATIONS

2011 ◽  
Vol 10 (03) ◽  
pp. 359-370 ◽  
Author(s):  
JUAN PANG ◽  
HU YANG ◽  
JING MA ◽  
RONGSHI CHENG
Keyword(s):  
Molecular Dynamics ◽  
Quantum Mechanics ◽  
Aqueous Solutions ◽  
Molecular Dynamics Simulations ◽  
Steric Effect ◽  
Conformational Transition ◽  
Methyl Group ◽  
Branched Chain ◽  
Dynamics Simulations ◽  
Different Levels

Poly(N-alkylacrylamide) is a group of thermo-sensitive polymers that include poly (N-isopropylacrylamide), poly(N-n-propylacrylamide), poly(N-isopropylmethacryl-amide), and so on. The polymers exhibit different levels of lower critical solution temperatures (LCST) in aqueous solutions. In this article, their monomers and oligomers with 10 repeating units are selected, respectively, to demonstrate the cause of different LCST levels of the polymers in aqueous solutions using molecular dynamics simulations and quantum mechanics calculations. The monomers have functional groups of different steric volume that greatly affect the conformational transition of chains and LCST levels of the polymers. A branched chain of N-propyl group in N-isopropylacrylamide and an additional methyl group at α-carbon in N-isopropylmethacrylamide both increase the steric effect, making it more difficult for monomers to draw closer and resulting in higher LCST levels of the polymers. In addition, the simulated results from their corresponding oligomers exhibit the similar trend to those from the monomers.

scholarly journals Quantitative interpretation of molecular dynamics simulations for X-ray photoelectron spectroscopy of aqueous solutions

2016 ◽  
Vol 144 (15) ◽  
pp. 154704 ◽  
Author(s):  
Giorgia Olivieri ◽  
Krista M. Parry ◽  
Cedric J. Powell ◽  
Douglas J. Tobias ◽  
Matthew A. Brown
Keyword(s):  
Molecular Dynamics ◽  
Aqueous Solutions ◽  
Molecular Dynamics Simulations ◽  
Photoelectron Spectroscopy ◽  
Quantitative Interpretation ◽  
X Ray ◽  
Dynamics Simulations

scholarly journals Molecular Dynamics Simulations of Hexadecane/Silicalite Interfaces

1998 ◽  
Vol 543 ◽  
Author(s):  
Edmund B. Webb ◽  
Gary S. Grest
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Concentration Profile ◽  
Interfacial Region ◽  
Absorption Length ◽  
Structure Of Molecules ◽  
Dynamics Simulations

AbstractThe interface between liquid hexadecane and the (010) surface of silicalite was studied by molecular dynamics. The structure of molecules in the interfacial region is influenced by the presence of pore mouths on the silicalite surface. For this surface, whose pores are the entrances to straight channels, the concentration profile for partially absorbed molecules is peaked around 10 monomers inside the zeolite. No preference to enter or exit the zeolite based on absorption length is observed except for very small or very large absorption lengths. We also found no preferential conformation of the unabsorbed tails for partially absorbed molecules.

Probing the Effect of Salt on Asphaltene Aggregation in Aqueous Solutions Using Molecular Dynamics Simulations

2018 ◽  
Vol 32 (8) ◽  
pp. 8090-8097 ◽  
Author(s):  
Xiaoyu Sun ◽  
Cuiying Jian ◽  
Yingkai He ◽  
Hongbo Zeng ◽  
Tian Tang
Keyword(s):  
Molecular Dynamics ◽  
Aqueous Solutions ◽  
Molecular Dynamics Simulations ◽  
Dynamics Simulations

scholarly journals Dispersion state phase diagram of citrate-coated metallic nanoparticles in saline solutions

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Sebastian Franco-Ulloa ◽  
Giuseppina Tatulli ◽  
Sigbjørn Løland Bore ◽  
Mauro Moglianetti ◽  
Pier Paolo Pompa ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Ionic Strength ◽  
Molecular Dynamics Simulations ◽  
Metal Nanoparticles ◽  
Metallic Nanoparticles ◽  
Free Energy Calculations ◽  
Coarse Grained ◽  
Solvent Accessible Surface Area ◽  
Dispersion State ◽  
Dynamics Simulations

Abstract The fundamental interactions underlying citrate-mediated chemical stability of metal nanoparticles, and their surface characteristics dictating particle dispersion/aggregation in aqueous solutions, are largely unclear. Here, we developed a theoretical model to estimate the stoichiometry of small, charged ligands (like citrate) chemisorbed onto spherical metallic nanoparticles and coupled it with atomistic molecular dynamics simulations to define the uncovered solvent-accessible surface area of the nanoparticle. Then, we integrated coarse-grained molecular dynamics simulations and two-body free energy calculations to define dispersion state phase diagrams for charged metal nanoparticles in a range of medium’s ionic strength, a known trigger for aggregation. Ultraviolet-visible spectroscopy experiments of citrate-capped nanocolloids validated our predictions and extended our results to nanoparticles up to 35 nm. Altogether, our results disclose a complex interplay between the particle size, its surface charge density, and the ionic strength of the medium, which ultimately clarifies how these variables impact colloidal stability.

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