Molecular dynamics study on iron oxide nanoparticles stabilised with Sebacic Acid and 1,10-Decanediol surfactants

Harris, Richard Anthony; Walt, Hendriëtte van der; Shumbula, Poslet

doi:10.1016/j.molstruc.2013.05.026

Cited by 29 publications

(17 citation statements)

References 15 publications

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“…(Table S.1 in the Supporting Information gives various calculated surfacecharge values for different NP sizes. 29 ) It is known that the negatively charged deprotonated carboxyl group of OA and the deprotonated lone pair of the amine group may form a bond with Fe 3+ and Fe 2+ atoms on the NP surface. 22,30,31 Because the NP with a diameter of 2.6 nm has the largest positive charge per surface area, 29 this NP size was selected for the simulations because it would give the best adsorption response.…”

Section: Theory Simulations and Experimentalmentioning

confidence: 99%

Analysis of the Interaction of Surfactants Oleic Acid and Oleylamine with Iron Oxide Nanoparticles through Molecular Mechanics Modeling

2015

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The interface interactions between surfactants oleic acid and oleylamine and magnetic nanoparticles are studied via molecular mechanics and dynamics. Mixtures of these two surfactants are widely advocated in the chemical synthesis of nanoparticles. However, the exact dynamic mechanism remains unclear. Here we report, for the first time, a comprehensive qualitative model showing the importance of acid-base complex formation between oleic acid and oleylamine as well as the presence of free protons in the engineering of nanoparticles of specific shapes and sizes. We show why critical parameters such as surfactant concentration may modify iron oxide nanoparticle shape and size and how this can be understood in the light of acid-base complex pair formation. We report on the influence these parameters have on both the in situ nanoparticle surface charge and zeta potential. Transmission electron microscopy (TEM), FTIR, and pH studies are used to confirm the validity of the calculated binding energies and number of acid-base pairs.

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Section: Theory Simulations and Experimentalmentioning

confidence: 99%

Analysis of the Interaction of Surfactants Oleic Acid and Oleylamine with Iron Oxide Nanoparticles through Molecular Mechanics Modeling

2015

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“…In particular, simulation of polymer functionalization of NPs is a complex task and requires sophisticated tools. In the literature, spherical brushes have been studied with Monte-Carlo and coarse-grained molecular dynamics (MD) simulations [58][59][60], PEGylation of gold NPs has been recently investigated both with coarse-grained and all-atoms MD [61,62], whereas classical MD runs have been carried out on PEG-coated silica NPs and on the interaction of iron oxides nanoparticles with different surfactants [63,64]. To the best of our knowledge, no studies on polymercoated curved TiO 2 nanoparticles exist.…”

Section: Introductionmentioning

confidence: 99%

Impact of surface curvature, grafting density and solvent type on the PEGylation of titanium dioxide nanoparticles

Selli

Motta

Valentin

2019

Journal of Colloid and Interface Science

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a b s t r a c t TiO 2 nanoparticles (NPs) are attracting materials for biomedical applications, provided that they are coated with polymers to improve solubility, dispersion and biocompatibility. Conformation, coverage density and solvent effects largely influence their functionality and stability. In this work, we use atomistic molecular dynamics simulations to study polyethylene glycol (PEG) grafting to highly curved TiO 2 NPs (2-3 nm) in different solvents. We compare the coating polymer conformations on NPs with those on (1 0 1) flat surfaces. In water, the transition from mushroom to brush conformation starts only at high density (r = 2.25 chains/nm 2 ). In dichloromethane (DCM), at low-medium coverage (r < 1.35 chains/ nm 2 ), several interactions between the PEG chains backbone and undercoordinated Ti atoms are established, whereas at r = 2.25 chains/nm 2 the conformation clearly becomes brush-like. Finally, we demonstrate that these spherical brushes, when immersed in water, but not in DCM, follow the Daoud-Cotton (DC) classical scaling model for the polymer volume fraction dependence with the distance from the center of star-shaped systems.

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“…Because 17R2 is a long chain molecule that has many local minima in the energy, a temperature annealing, that is, thermostatting the fluid at 500 K for 0.3 ns (300 000 timesteps), was therefore applied for confined lubricant to overcome energy barriers and move into the optimal equilibrium configuration. 29 In the second stage, the temperature was reduced to 300 K to obtain stable solution at room temperature, while the system was slowly compressed for 2.6 ns (2 600 000 timesteps) by applying a constant load. This applied load corresponds to pressures between 0.25 and 1.0 GPa acting on the top rigid layer.…”

Section: ■ Introductionmentioning

confidence: 99%

Tribological Behavior of Aqueous Copolymer Lubricant in Mixed Lubrication Regime

Zhu

et al. 2016

ACS Appl. Mater. Interfaces

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Although a number of experiments have been attempted to investigate the lubrication of aqueous copolymer lubricant, which is applied widely in metalworking operations, a comprehensive theoretical investigation at atomistic level is still lacking. This study addresses the influence of loading pressure and copolymer concentration on the structural properties and tribological performance of aqueous copolymer solution of poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) (PPO-PEO-PPO) at mixed lubrication using a molecular dynamic (MD) simulation. An effective interfacial potential, which has been derived from density functional theory (DFT) calculations, was employed for the interactions between the fluid's molecules and iron surface. The simulation results have indicated that the triblock copolymer is physisorption on iron surface. Under confinement by iron surfaces, the copolymer molecules form lamellar structure in aqueous solution and behave differently from its bulk state. The lubrication performance of aqueous copolymer lubricant increases with concentration, but the friction reduction is insignificant at high loading pressure. Additionally, the plastic deformation of asperity is dependent on both copolymer concentration and loading pressure, and the wear behavior shows a linear dependence of friction force on the number of transferred atoms between contacting asperities.

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Molecular dynamics study on iron oxide nanoparticles stabilised with Sebacic Acid and 1,10-Decanediol surfactants

Cited by 29 publications

References 15 publications

Analysis of the Interaction of Surfactants Oleic Acid and Oleylamine with Iron Oxide Nanoparticles through Molecular Mechanics Modeling

Analysis of the Interaction of Surfactants Oleic Acid and Oleylamine with Iron Oxide Nanoparticles through Molecular Mechanics Modeling

Impact of surface curvature, grafting density and solvent type on the PEGylation of titanium dioxide nanoparticles

Tribological Behavior of Aqueous Copolymer Lubricant in Mixed Lubrication Regime

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