Molecular simulation study of the curling behavior of the finite free-standing kaolinte layer

Since kaolinite nanolayers potentially have many important applications, it is crucial to determine the factors that govern their curling behavior. The curling of a single-layer, free-standing kaolinite nanoparticle consisting of nearly 1 million atoms is studied with classical molecular dynamics simulation. Two up-to-date force fields are employed to describe the atomic interactions in the clay. The influence of force field details and of the use of different treatments of interactions (long range correction, potential cut-off radius) on the curling direction is systematically examined. That includes a practically infinite potential cut-off, which means that all atomic interactions are considered explicitly. For every inspected case, the structure is characterized by the overall shape of the particle, the axis of roll-up and particular bond lengths and angles. Both of the two possible curling directions are detected in the present simulations, which contradicts the crystallographic assumption that the constituent tetrahedral sheet can exclusively be on the concave side of curled kaolinite nanolayers.