Co-occurrence of photochemical and thermal effects during laser polymer ablation via a 248-nm excimer laser

Polypropylene PP.was ablated using a 248-nm KrF excimer laser with a fluence in the range of 0.4–2 Jrcm2 and at a repetition rate of 10 Hz. It has been found that both photochemical and thermal effects are co-operative during laser ablation process, evidenced by the existence of thermal affected zone TAZ., together with ablative zone AZ.and unaffected zone UAZ.in the ablated crater. Increment of both fluence and the number of pulses leads to a more striking thermal effect, demonstrated by the spatial expansion of rim for PP. Relative importance of photochemical and thermal effects was theoretically discussed. q2000 Elsevier Science B.V. All rights reserved