Spontaneous swelling of layered nanostructures by a polymer melt

Polymer layered silicate nanocomposites may be formed by annealing layered silicate particles with a polymer melt. Polymer molecules leave the bulk me lt and intercalate between the silicate layers, producing a structure in wh ich polymers are confined on the nanometer scale by the silicate layers. We report here molecular dynamics simulations of this formation process, whic h is modeled by the flow of polymer from a bulk melt into a slit whose wall s are maintained at constant pressure and whose surfaces are decorated by g rafted short hydrocarbon chains. The results are compared with x-ray diffra ction studies of the intercalation of high molecular weight polymers into o rganically modified silicates, and with a previous simulation of the flow o f polymer molecules from a bulk melt into a slit of fixed dimension. (C) 19 99 American Institute of Physics. [S0021-9606(99)70745-2].