Molecular dynamic simulations of the poly(dimethylsiloxane) (PDMS)/water system
M. Groombridge, M. Schneemilch, N. Quirke
Imperial College, UK
molecular dynamics pdms wetting
A well defined model of the PDMS surface was constructed by compressing a single PDMS chain between two hard elastic boundaries, forming tile shaped rigid solid substrates which were then arrayed to form larger surfaces. The oxidizing process was modeled by replacing methyl groups on the PDMS chain close to the surface with hydroxyl groups. The surfaces were brought into contact with SPC/E model water molecules in several configurations. Single-phase simulations were conducted in a slit pore under equilibrium conditions and under an external gravitational type field. Sessile drops were equilibrated on the surface and the microscopic contact angle determined as function of drop size. The three-phase flow behavior was studied in the slit pore configuration. Flow was created by Poiseuille and Couette methods. Finally, spontaneous flow was induced along a surface wettability gradient created by aligning a series of tiles in order of increasing degree of oxidation.
Nanotech 2008 Conference Program Abstract