Non-equilibrium molecular dynamics of nanoscale lubricants

My current research involves the use of non-equilibrium molecular dynamics (NEMD) simulations to study the tribological properties of alkylsilane monolayers as a next-generation lubricant for nanoscale devices. My research on these materials attempts to address three primary areas:

1. Monolayer degradation. How can monolayer degradation be sufficiently examined with molecular dynamics, and what monolayer properties lead to increased lifetimes under shear?
2. Friction mechanisms at asperity contacts. What mechanisms leads to friction and wear of monolayers in the presence of nanoscale roughness/asperities? How are these mechanisms affected by the monolayer chemistry?
3. Influence of monolayer chemistry on friction forces. By examining structure-property relationships, screening monolayer films of various chemistries and examining the resultant frictional forces, can we determine monolayer chemistries that are ideal for lubrication?

Friction force vs. normal force curves and cross-sectional snapshots for systems featuring (a) a hemispherical tip in contact with a monolayer on an amorphous substrate, (b) a blunted tip in contact with a monolayer on an amorphous substrate, and (c) a blunted tip in contact with a monolayer on a crystalline substrate. Plots are obtained by shearing tips across the monolayers under a constant velocity and normal load and measuring friction forces. (d) Inter-surface separation (the distance between the tip apex and the top of the surface) for the three systems during shear. This figure was taken from my recent publication in Langmuir which can be found here.

Coarse-grained force fields for amorphous silica nanoparticles

Description coming soon!