Resonant infrared pulsed-laser deposition of polymer films using a free-electron laser

Thin films of polyethylene glycol (MW 1500) have been prepared by pulsed-la ser deposition (PLD) using both a tunable infrared (lambda =2.9 mum, 3.4 mu m) and an ultraviolet laser (lambda =193 nm). A comparison of the physicoch emical properties of the films by means of Fourier transform infrared spect roscopy, electrospray ionization mass spectrometry, and matrix-assisted las er desorption and ionization shows that when the IR laser is tuned to a res onant absorption in the polymer, the IR PLD thin films are identical to the starting material, whereas the UV PLD show significant structural modifica tion. These results are important for several biomedical applications of or ganic and polymeric thin films. (C) 2001 American Vacuum Society.