TY - JOUR A1 - Urech, L. A1 - Lippert, T. A1 - Wokaun, A. A1 - Martin, Sven A1 - Mädebach, Heinrich A1 - Krüger, Jörg T1 - Removal of doped poly(methylmetacrylate) from tungsten and titanium substrates by femto- and nanosecond laser cleaning JF - Applied surface science N2 - The influence of different laser pulse lengths on the removal of a polymer layer from metal substrates was investigated. As model systems, doped poly(methylmetacrylate) (PMMA) on titanium and tungsten substrates were selected. The ablation threshold and irradiation spot morphology of titanium and tungsten were compared for femtosecond (fs) and nanosecond (ns) laser irradiation and different pulse numbers. Nanosecond laser treatment resulted in a non-homogeneous surface morphology for both titanium and tungsten substrates. Femtosecond irradiation of tungsten revealed a homogeneous ablation spot with little changes in the surface morphology. For titanium, the formation of columnar structures within the irradiation spot was observed. Two different dopant concentrations were used for PMMA to achieve an equal linear absorption coefficient for the femto- and nanosecond laser wavelengths of 790 and 1064 nm. The best results were achieved for the removal of doped PMMA by femtosecond laser irradiation, where only a minimal modification of the metal surface was detected. In the case of nanosecond laser exposure, a pronounced change of the structure was observed, suggesting that damage-free cleaning of the selected metal may only be possible using femtosecond laser pulses. Different experimental parameters, such as laser fluence, pulse repetition rate and sample speed were also investigated to optimize the cleaning quality of doped PMMA from tungsten substrates with femtosecond laser pulses. KW - Poly(methylmetacrylate) KW - Laser treatment KW - Tungsten KW - Titanium KW - Femtosecond PY - 2006 DO - https://doi.org/10.1016/j.apsusc.2005.07.109 SN - 0169-4332 SN - 1873-5584 VL - 252 IS - 13 SP - 4754 EP - 4758 PB - North-Holland CY - Amsterdam AN - OPUS4-12368 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -