Modelling the interaction between the poly(octadecyl acrylate) inhibitor and an n-octacosane crystal

The interaction between a growth inhibitor (poly(octadecyl acrylate)) and t he surfaces of a paraffin crystal has been modelled using a molecular dynam ics technique. A dimer unit of the inhibitor was found to interact strongly with the paraffin crystal surfaces, with good crystallographic matching, a nd it was readily incorporated into the crystal. The inhibitor introduced s ome distortion into the local alkane structure and there was an increase in the average energy of the alkane molecules close to the inhibitor. Crystal growth was simulated by the addition of molecules to the surface; both sin gle molecule addition and crystal layer addition were considered. During th e growth simulations the open conformation of the inhibitor was found to st abilize a configuration in which a number of alkane molecules spanned the g ap between the crystal lamellae. Such an extended defect may play a signifi cant role in the inhibitor mechanism.