Low molecular weight polystyrene (∼10 kDa) was ablated with a free-electron laser at 3.31 and 3.43 μm and deposited as thin films on Si(100) substrates. The vibrational bands at 3.31 and 3.43 μm correspond to phenyl-ring CH and backbone CH2 modes, respectively. Even though the absorption coefficients of these two modes are nearly the same, the ablation yield was approximately 50% higher for the ring-mode excitation compared with the backbone mode. Based on spectral line width, the ring-mode lifetime is approximately triple that of the backbone mode, leading to a higher spatiotemporal density of vibrational excitation that more effectively disrupts the relatively weak Van der Waals bonds between neighboring polymer chains and consequently to higher ablation efficiency of the ring mode. Molecular weight assays of the deposited films showed that relatively little bond scission occurred and that the average molecular weight of the films was similar to that of the starting material.

This work focuses on the deposition of organic thin films by matrix assisted pulsed laser deposition. In particular, an Er:YAG laser is used and the results compare more than favorably with those obtained when using an ArF (193 nm) laser. The deposition of polyethylene glycol, fluropolyol, polyaniline (emeraldine salt), and calf thymus DNA is reviewed and discussed.

Conducting polyaniline thin films have been deposited by a laser-based vaporization technique. The films have been characterized by infrared spectroscopy, UV-Vis spectroscopy, four-point conductivity measurements, thermogravimetric analysis, and fluorescence measurements. In addition, the films have been characterized with respect to their photoconductive response to 532-nm laser light. It is found that the films exhibit persistent photoconductivity and it is proposed that defect base sequences may be responsible for the charge localization that results in such a photoconductive response.

A porphyrazine and a series of tetracationic porphyrazines, metallated and nonmetallated, were synthesized. The neutral tetrapyridino porphyrazine was obtained in a yield of 45%. The tetracationic nonmetallated tetraethanoltetrapyridino porphyrazinium iodide was obtained in a yield of 79%. The metallated porphyrazines are (Mn+2, Cu+2, Co+2, Zn+2) = M. M-Tetraethanoltetrapyridino porphyrazinium iodide was obtained in a yield of 78%, 69%, 75%, and 72%, respectively. The porphyrazine and the tetracationic porphyrazines, nonmetallated and metallated, were characterized by elemental analysis, ESI-MS, MALDI-MS, FTIR, and UV-VIS.

Fluoropolyol, a sorbent chemoselective oligomer, has been deposited using a matrix-assisted laser-based deposition technique. A comparison of films deposited with infrared (2.94 μm) and ultraviolet (UV) (193 nm) radiation shows that photochemical and/or photothermal modification of the oligomer occurs for the UV-deposited films while the IR-deposited films appear to be identical to the starting material. In addition, it is shown that even ablating the matrix alone causes a film to be deposited when using a UV laser. Therefore, unless photochemical interactions are a desired outcome, the use of a UV laser for most matrix-assisted laser ablation and deposition techniques is unfavorable.