Molecular Dynamics Simulations of Silver Nanoparticles of Cubic and Bipyramidal Shape

Abstract

The crystalline structure, the perfect face-centered cubic (fcc) atom packing and macroscopic morphological stability of sharp-edged silver nanoparticles of cubic and bipyramidal shapes were compared against quasi-spherical nanoparticles by using classical molecular dynamics (MD) simulations. A series of silver nanocubes (AgNCs) and nanobipyramides (AgNBs) of different sizes varying from 44 up to 1156 atoms were considered. Our MD simulations revealed that starting from the preformed perfect crystalline structures the initial shape was preserved for cubic and bipyramidal nanoparticles composed of more than 256 atoms. Surprisingly, the rapid loss of the cubic-shape morphology and transformation into the non-fcc-structure were found for the smaller AgNCs composed of less than 172 atoms. No such loss of the preformed crystalline structure was noticed for bipyramidal and quasi-spherical nanoparticles. The analysis of the binding energy of the outermost Ag surface atoms suggests that the loss of the perfect cubic shape, rounding and smoothing of sharp edges and corners were driven by the tendency towards the increase in their coordination number.

pH-Responsive Coating of Silver Nanoparticles with Poly(2-(N,N-dimethylamino)ethyl methacrylate): The Role of Polymer Size and Degree of Protonation

“…The parameters of the LJ potentials for Ag–Ag were taken from our recent studies. ,,,, For mixed non-bonded interactions between Ag and PDMAEMA, and water atoms, the Lorentz–Berthelot combination rules were used …”

pH-Controllable Coating of Silver Nanoparticles with PMMA-b-PDMAEMA Oligomers: A Molecular Dynamics Simulation Study

“…An AgNP core model was composed of neutral Ag atoms with zero partial charges. , The repulsion and dispersion terms of nonbonded interactions between a pair of Ag atoms were computed by using the classical Lennard-Jones (LJ) 12–6 pairwise potential energy function. The parameters of the LJ potentials for Ag–Ag were taken from our recent studies. ,,,,, For mixed nonbonded interactions between Ag and PMMA- b -PDMAEMA and water atoms, the Lorentz–Berthelot combination rules were used …”

Polarizable force field for molecular dynamics simulations of silver nanoparticles

“…The initial values of q and l 0 were taken from the original study [44]. The nonbonded interaction parameters Ag-Ag σ=0.2964 nm and ε=19.05865 kJ/mol were taken from our recent works [9,24]. However, both parameters σ and ε were assigned to zero for the virtual site.…”

“…Molecular dynamics (MD) simulation, in partnership with an experiment, has become an essential tool for studying metal nanoparticles at the atomic level [5]. Atomic-scale theoretical methods can provide important insight to the solution-phase synthesis of silver nanostructures that involves the seeded growth [6][7] and the morphological stability [8][9], as well as adsorption of stabilizing agents and solvent molecules onto inorganic metal nanocrystals [10][11][12]. Numerous MD simulation studies of silver and gold nanoparticles protected by organic ligand monolayers [13][14][15][16][17][18], synthetic polymers [19][20][21][22][23][24][25][26], and peptides [27][28][29][30] have been conducted in the last decade.…”