Dear all:

  I want to build a meso-scale montmorillonite-water-ion system model with the DPD tool in MS 6.0 like the way noted in Scocchi et al. paper [Scocchi, G., Posocco, P., Fermeglia, M., and Pricl, S. 2007. Polymer-clay nanocomposites:  A multiscale molecular modeling approach, Journal of Physical Chemistry B, Vol. 111, No. 9, pp. 2143-2151.]

  As their introductions, "To represent the clay platelets, we made use of the available software option of including a repulsive wall in the simulation box, perpendicular to the z-axis at the origin. Further, we introduced a bead with no connectivity and no repulsion toward the wall, in order to fill the space between the two wall surfaces, thus representing a MMT platelet"

  In fact, I can find the available MS option of "Repulsive wall at cell boundary" in the System tab of DPD calculation window, but I don't know how to set the two walls' space for inserting MMT bead into it, like the space between the soild and dash line in the following figures.

  So I hope you can give me some detail suggestions.

  Thank you very much!