Structural properties of atactic polystyrene adsorbed onto solid surfaces

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: α-quartz, graphite, and amorphous silica. Our investigation was restricted to atactic polystyrene. Our results show that the density and structural properties of side chains depend on the type of surface. An excess of phenyl rings is observed near the α-quartz substrate while the film adsorbed on graphite is depleted in C(6)H(5). 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.

Self-Assembled Copolymer Adsorption Layer-Induced Block Copolymer Nanostructures in Thin Films

“…On the other hand, a shoulder peak of N 1s at 397.8 eV is more dominant in P2VP­(spin) TA , as indicated with the green arrow in the first and second rows of Figure c, respectively. There are various possibilities for the origin of this peak, and the most probable case is that a hydroxyl group of the native oxide layer interacts with the π bond in the aromatic pyridine ring, thus forming a well-known hydrogen bonding of π···H–O. − It should be noted that the origins of the H-bonding for adsorbed layers can be different depending on how the adsorbed layers are formed: whether they are transferred from the air/water interface or obtained from a spin-coated film. A thorough and complete XPS analysis is provided in the Supporting Information (see the Discussions section; Figures S6–S8, and Table S2).…”

Dynamics of various polymer–graphene interfacial systems through atomistic molecular dynamics simulations

“…For this reason in the last few years several simulation works concerning the properties of various polymer-graphene (or polymer-graphite) nanostructured systems have appeared in the literature. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] The study of the dynamics of polymer chains close to graphene layers is of special importance, since friction at the interface determines the dynamical, the rheological as well as the mechanical properties of the hybrid system.…”

Structure and dynamics of poly(methyl methacrylate)/graphene systems through atomistic molecular dynamics simulations

“…For a series of different polymers authors found that both CNTs and GNSs induce crystallization of alkane molecules in the range of temperatures [400-500]K, while CNT's presented a stronger effect on crystallization. The structure of atactic polystyrene (PS) on three different substrates, a-quartz, amorphous silica and graphite has been also studied through detailed atomistic simulations by Tatek et al (Tatek et al 2011). In this work the effect of the type of the different surfaces on the density, the structure and the conformational properties of PS has been discussed.…”