Journal or Book Title
Journal of Chemical Information and Modeling
Experimental results show that the adsorption of the self assembled monolayers (SAMs) on a gold surface induces surface stress change that cause a deformation of the underlying substrate. However, the exact mechanism of stress development is yet to be elucidated. In the present study, multiscale computational models based on molecular dynamics (MD) simulations are applied to study the mechanism governing surface stress change. Distinct mechanisms for adsorption induced surface deformation, namely inter chain repulsion and thiol-gold interaction driven gold surface reconstruction, are investigated. Two different inter-atomic potentials, embedded atom method (EAM) and surface embedded atom method (SEAM), are used in the MD simulations to study the reconstruction induced surface stresses. Comparison of the predicted surface stress changes, resulting from MD and continuum mechanics based models, with observed experimental response, indicate that a modified SEAM based multiscale model can better capture the surface stress changes observed during alkanethiol SAM formation and gold surface reconstruction is the primary factor behind the surface stress change. Inter chain repulsions of SAM are found to have minimal contribution. Also, both the simulations and experiments show that surface stress change increases with surface coverage density and larger grain size.
American Chemical Society
Zhao, Yue; Gosai, Agnivo; Kang, Kyungho; and Shrotriya, Pranav, "Multiscale Modeling Reveals the Cause of Surface Stress Change on Microcantilevers Due to Alkanethiol SAM Adsorption" (2020). Mechanical Engineering Publications. 422.