Molecular Dynamics Simulation of Nanoconfinement Induced Organization of n-Decane

Abstract

Molecular dynamics (MD) simulations are used to study the behavior of n-decane under sub-10 nm confinement between two gold {111} surfaces. This confinement and dielectric medium are characteristic of those used in nanoscale electromachining (nano-EM) processes; thus, it is important that the behavior of the nanoconfined dielectric medium be investigated for better process understanding. Results obtained via MD simulations indicate that, when confined down to a thickness less than 1 nm, the mechanical boundary conditions trigger organization in the n-decane medium, resulting in two distinct molecular layers. The n-decane chains lie flat on the {111} gold surfaces and show preferred orientation in the close-packed 110 crystallographic directions. A 4-fold increase in the maximum local density as compared with the experimental bulk (liquid) density is observed at the interface between the molecular medium and the gold {111} surfaces, regardless of confinement spacing. Radial distribution function curves are used to quantitatively examine organization of the medium into molecular layers. The deliberate introduction of ledges (atomic steps) on the gold surface triggers a preferred alignment of the n-decane chains toward the boundaries of the ledges.

A molecular dynamics simulation of boundary lubrication: The effect of n-alkanes chain length and normal load

“…2b, this densely packed state resembles a solid-like structure in the lubricant molecules because of the strong solid-fluid interaction. Kalyanasundaram et al [22] reported similar results. As the chain length increased the lubricant molecules tended to accumulate around the asperities and join the molecules from the opposite wall, as shown in Fig.…”

Thin film lubrication of hexadecane confined by iron and iron oxide surfaces: A crucial role of surface structure

“…Over the last two decades, there have been extensive studies of thin film lubrication of alkane between metal tribo-pairs using molecular dynamics (MD) method. [4][5][6][7] Attempts have been made to assess the role of Fe 2 O 3 (001) surfaces in thin film lubrication; [8][9][10] however, a thorough understanding of tribological and structural properties of hexadecane on different iron and iron oxides surfaces as well as their surface orientations is still missing. Additionally, previous investigations employed a simple model, in which each methyl or methylene group was described using a united-atom (UA) model and tribo-surfaces were modeled by harmonic spring without the consideration of electrostatic contribution.…”

Molecular dynamics simulation of mechanism of nanoparticle in improving load-carrying capacity of lubricant film

“…Intra-molecular interactions, including bond stretching, angle bending and dihedral angle torsion are governed by harmonic form, theta harmonic form and cosine polynomial form, respectively [25]. The corresponding equations and parameters are provided in Table 1.…”

“…Savio et al [24] investigated the friction properties of the last lubricant layers prior to direct contact of surfaces by considering several parameters. Kalyanasundaram et al [25] simulated the organizational behavior of n-decane for different gap separations (sub-10 nm) and found that the medium structures were affected by mechanical boundary conditions and crystallographic directions. Minimal investigations exist on anti-wear and anti-friction mechanisms of nanoparticles.…”