Microstructure and intercalation dynamics of polymer chains in layered sheets

Abstract

The layered polymer nanocomposites have attracted great interest from scientists due to their unique properties. However, the formation mechanism of these nanocomposites in the intercalation process is not fully understood yet. In this work, we simulate the intercalation processing of polymer chains into two layered sheets. By systematically tuning the polymer–sheet interaction, temperature, chain length, organic surfactant modification and interlayer distance, we found that the intermediate polymer–sheet interaction, low polymer molecular weight and large interlayer distance would enhance the intercalation kinetics. However, the presence of surfactants promotes the intercalation process of chains into layered sheets only when the interaction between polymer and surfactants is strong enough. In the intercalation process, the polymer chain first elongates and then contracts. To uncover the mechanism of aggregation and formation of layered sheets–polymer network, we examine the formation of bridge chains between layered sheets. Generally, the polymer chain does not adsorb totally on one single layer, but crosses over from one layer to another. Moreover, the number of bridge chains monotonically decreases with the increase of the polymer–sheet interaction and interlayer distance, but increases with the polymer chain length. It is expected that the structural and dynamic behavior of polymer chains intercalated into the layered sheets could deepen our understanding of polymer nanocomposites filled with layered sheets.