Laser ablation of polystyrene films studied with atomic force microscopy and quartz crystal microbalance

Atomic force microscopy (AFM) and quartz crystal microbalance (QCM) were used to study laser ablation and processing of polystyrene films in ambient environment. A UV nitrogen laser (wavelength centered at 337 nm) was used for single pulse treatment of polymer films on the surface of a quartz crystal. Laser pulse energy was regulated by a diaphragm. Laser ablations were performed by illuminating a chosen area of polystyrene film through a mask. The amount of mass removed are monitored using the quartz microbalance. The morphologies of processed surface were analyzed using an optical microscope and an atomic force microscope. From analysis of resonant frequency of quartz crystal microbalance, the ablation threshold was found 0.095+/-0.011J/cm2. Above the threshold the ablation rate is proportional to the fluence with proportionality coefficient of 73.43·10-10 gcm2/J. The laser ablation increases the roughness of surface in the illuminated areas.