Fs-laser processing of polydimethylsiloxane

Abstract

We present an experimental analysis on surface structuring of polydimethylsiloxane films with UV (263nm) femtosecond laser pulses, in air. Laser processed areas are analyzed by optical microscopy, SEM, and μ-Raman spectroscopy. The laser-treated sample shows the formation of a randomly nanostructured surface morphology. μ-Raman spectra, carried out at both 514 and 785nm excitation wavelengths, prior and after laser treatment allow evidencing the changes in the sample structure. The influence of the laser fluence on the surface morphology is studied. Finally, successful electro-less metallization of the laser-processed sample is achieved, even after several months from the laser-treatment contrary to previous observation with nanosecond pulses. Our findings address the effectiveness of fs-laser treatment and chemical metallization of polydimethylsiloxane films with perspective technological interest in micro-fabrication devices for MEMS and nano-electromechanical systems

XPS and μ-Raman study of nanosecond-laser processing of poly(dimethylsiloxane) (PDMS)

“…At higher fluence and number of pulses broad bands assigned to the D band of amorphous carbon and the G band of polycrystalline and microcrystalline graphite also appear (Fig. 2a), confirming findings described before [9,10,14,15]. Moreover, spectra variations are XPS and l-Raman analyses are conducted about a month after the laser treatment.…”

“…(iv) An increase of Si in the EDS spectra was observed acquired on PDMS irradiated with Nd:YAG laser in comparison with those on native PDMS [10]. Laser treatment is used in order to facilitate selective metallization of the areas activated in this way [11][12][13][14][15].…”

“…Its intensity increases with the number of the pulses and the laser fluence. Moreover, in the l-Raman spectra broad bands appear between 1320 cm À1 and 1603 cm À1 depending on the experimental conditions, which can be assigned to D band of the amorphous carbon and the G band of polycrystalline and microcrystalline graphite, respectively [9,10,14,15].…”

“…After irradiation of PDMS with a Nd:YAG laser, the l-Raman spectrum presents a new peak at 516 cm À1 , which can be assigned to nanocrystalline silicon [9,10,13,14]. The sharp peak between 512 and 518 cm À1 appears also in the case of processing with visible light (VIS) of nanosecond Nd:YAG laser (532 nm) and femtosecond laser (527 nm), which is the first observation of c-Si formation by irradiation of PDMS with VIS femtosecond pulses [15].…”

Incubation phenomena during UV‐pulse excimer laser processing of silicone elastomers

“…The UV‐pulse laser processing of medical grade silicone elastomers is one of the most successful modern methods allowing selective transformation of the material surface into hydrophilic without affecting their important specific bulk properties. Particularly the ablated areas are activated for metallization via electroless (autocatalytic) plating …”