No abstract

No abstract

No abstract

Laser is a promising technique used for biopolymer surface modification with micro and/or nano features. In this work, a 193 nm excimer laser was used for poly (ethylene terephthalate) (PET) surfaces chemical patterning. The ablation threshold of the PET film used in the experiments was 62 mJ/cm(2) measured before surface modification. Surface chemical patterning was performed by irradiating PET film in a vacuum chamber filled with ammonia at the flux of 10, 15, 20, 25 ml/min. Roughness of the surface characterized by profilometry showed that there were no significant observed change after modification comparing original film. But the hydrophilicity of the surface increased after patterning and a minimum water contact angle was obtained at the gas flux of 20 ml/min. FT-IR/ATR results showed the distinct amino absorption bands presented at 3352 cm(-1)and 1613 cm(-1) after modification and XPS binding energies of C(1s) at 285.5 eV and N(1s) at 399.0 eV verified the existence of C-N bond formation on the PET film surface. Tof-SIMS ions mapping used to identify the amine containing fragments corroborates that amino grafting mainly happened inside the laser irradiation area of the PET surface. A hypothesized radical reaction mechanism proposes that the collision between radicals in ammonia and on the PET surface caused by the incident laser provokes the grafting of amino groups.

Laser macrostructuration of titanium alloy surfaces appears to promote bone apposition and may therefore constitute a promising surface modification strategy. In animal models, the natural process of titanium surface oxidation, because of physiologic fluids, alters properties observed in vitro with cells.