Molecular Dynamics Modeling of Kaolinite Particle Associations

We developed a new procedure for calculating finite-size kaolinite particles, their associations with complex surface chemistry, and the natural flexibility of sheets within a particle using a large-scale atomic/molecular massively parallel simulator. For the first time, all possible particle associations previously described in the literature were obtained using an atomic method. The structural configurations obtained were shifted face-face, angular edge-edge, corner-corner, and shifted face-face-face booklet associations. The simulations showed that if the initial angle between two interacting particles is less than 45°, the particles will form layer-to-layer aggregates. If the angle is larger than 60°, the particles will form an angular arrangement. The densities of kaolinite arrangements with dense and loose packings were evaluated as a function of the structure. The densest structures, as expected, were the layered structures, with four and two layers. The density of the shifted face-face packing was about the same density as the two. The face-face-face association showed lower density, and the angular edge-edge association showed a 3 times lower density than the densest, four-layer structure.