Publication: Structural Properties of Atactic Polystyrene Adsorbed onto Solid Surfaces

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Title	Structural Properties of Atactic Polystyrene Adsorbed onto Solid Surfaces
Authors/Editors*	YB Tatek and M Tsige
Where published*	The Journal of Chemical Physics
How published*	Journal
Year*	2011
Volume	135
Number
Pages	174708
Publisher
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Abstract	In the present work, we are studying the local conformation of chains in a thin film of polystyrene adsorbed on a solid substrate by using atomistically detailed simulations. The simulations are carried out by using the readily available and massively parallel molecular dynamics code known as LAMMPS . In particular, a special emphasis is given to the density and orientation of side chains (which consist of phenyl groups and methylene units) at solid/polymer and polymer/vacuum interfaces. Three types of substrates were used in our study: Î±-quartz, graphite, and amorphous silica. Our investigation was restricted to atactic polystyrene. Our results show that the density and struc- tural properties of side chains depend on the type of surface. An excess of phenyl rings is observed near the Î±-quartz substrate while the film adsorbed on graphite is depleted in C6 H5 . Moreover, the orientation of the rings and methylene units on the substrate/film interface show a strong dependence on the type of the substrate, while the rings at the film/vacuum interface show a marked tendency to point outward, away from the film. The results we obtained are in a large part in good agreement with previous experimental and simulation results.