Molecular mechanics simulation on the nanoindentation of POSS hybrid polystyrene

Mechanical behaviors of the nanoindentaion of polystyrene (PS) and Polyhedral Oligomeric Silsesquioxane (POSS) reinforced PS are presented by the means of molecular mechanics simulations. The load-displacement curves of the two kinds of polymers are obtained. The curves show that the loads increase with the displacement in serrated pattern. Furthermore, the hardness of the polymers are calculated from the load-displacement curves combined with the constructional deformations of the materials. A simple formula connected the hardness with the indentation depth is adopted and verified by the known hardness-depth curves of several common polymers. Based on the equation, the calculated hardness of POSS hybrid PS is much higher than that of PS, which indicates that the POSS units play a rather important role in the enhancement of the hardness of PS.