Density enhancement in ion implanted PVT (polyvinyltoluene)

Ion beam irradiation of polyvinyltoluene (PVT) induces strong chemical and physical modifications. Using 50-300 keV proton, helium and nitrogen beams, at low doses, below 10(12) ions/cm(2), dehydrogenation and molecular emiss ion of CxHy groups occurs. At higher doses the irradiation induces surface roughness and density increase of the polymer. Main emitted species are H-2 , C2H2 and C3H5. At high ion doses the polymer density may reach 195% of it s initial value and the roughness may reach micron dimensions. The densific ation process is investigated as a function of the ion fluency and ion stop ping power.