Molecular dynamics study of polystyrene bond-breaking and crosslinking under C60 and Arn cluster bombardment

Molecular dynamics computer simulations are used to elucidate the bond-breaking and crosslinking processes induced by 2.5 keV C60 and Arn cluster bombardment in an amorphous sec-butyl-terminated polystyrene sample. The obtained results indicate that replacement of C60 by Ar18 or Ar60 projectiles leads to the decrease of the number of broken bonds and, hence, to the decrease of formation of new intra- and intermolecular (crosslinking) bonds. When the number of atoms in the Arn cluster is increased from 60 to 250 or more, the total number of broken bonds and the total number of newly created bonds reach a zero value. Additional comparison to the case of a fullerite crystal reveals that the change of material properties leads to almost 7.5-fold reduction of the efficiency of the crosslinking process.