Mechanism of resonant infrared laser vaporization of intact polymers

摘要

Experiments on pulsed laser vaporization of many different kinds of polymers have demonstrated that it is possible to eject intact polymers into the ambient, whether air or vacuum, by resonant pulsed laser excitation, using both neat and matrix targets. Two recent studies of resonant infrared ablation - one on polystyrene, the other on poly(amic acid), the precursor for the thermoset polyimide - show moreover that the ablation process is both wavelength selective and surprisingly non-energetic, especially compared to ultraviolet laser ablation. We propose a wavelength-selective photo-thermal mechanism involving breaking of intermolecular hydrogen bonds that is consistent with these observations.