Wu G, Paz M D, Chiussi S, Serra J, González P, Wang Y J, Leon B
Department of Applied Physics, University of Vigo, Rua Maxwell, Vigo, Spain.
J Mater Sci Mater Med. 2009 Feb;20(2):597-606. doi: 10.1007/s10856-008-3600-5. Epub 2008 Oct 14.
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.
激光是一种很有前景的技术，可用于对生物聚合物表面进行具有微米和/或纳米特征的改性。在这项工作中，使用193纳米准分子激光对聚对苯二甲酸乙二酯（PET）表面进行化学图案化处理。实验中所用PET薄膜在表面改性前测得的烧蚀阈值为62毫焦/平方厘米。通过在充满氨气的真空腔中以10、15、20、25毫升/分钟的通量照射PET薄膜来进行表面化学图案化。通过轮廓仪表征的表面粗糙度表明，与原始薄膜相比，改性后未观察到明显变化。但图案化后表面的亲水性增加，在20毫升/分钟的气体通量下获得了最小水接触角。傅里叶变换红外光谱/衰减全反射（FT-IR/ATR）结果表明，改性后在3352厘米-1和1613厘米-1处出现了明显的氨基吸收带，PET薄膜表面C（1s）的X射线光电子能谱（XPS）结合能为285.5电子伏特，N（1s）的结合能为399.0电子伏特，证实了表面形成了C-N键。用于识别含胺片段的飞行时间二次离子质谱（Tof-SIMS）离子图谱证实，氨基接枝主要发生在PET表面的激光照射区域内。一种假设的自由基反应机制提出，入射激光导致氨气中的自由基与PET表面的自由基之间发生碰撞，从而引发氨基的接枝。
