Ammonia RF-plasma on PTFE surfaces: Chemical characterization of the species created on the surface by vapor-phase chemical derivatization
Ammonia RF-plasma on PTFE surfaces: Chemical characterization of the species created on the surface by vapor-phase chemical derivatization
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DOI：
10.1021/jp011607k
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发表时间：
2001-12-20
影响因子：
3.3
通讯作者：
Laroche, G
中科院分区：
文献类型：
--
作者：
Chevallier, P;Castonguay, N;Laroche, G
采用圆柱形射频辉光放电等离子体处理系统对ePTFE人工动脉内表面进行氨改性，以改善其生物相容性。为了更好地理解这种类型的处理油表面的效果，还在PTFE膜上进行RF等离子体。然后用XPS表征表面化学组成。初步分析表明，15%的表面原子被氮取代（N/C比为0.3），而F/C比从2降低到0.7-0.5，这表明经处理的表面呈现不同的化学物质，例如胺、亚胺、酰胺、酸基团和不饱和度。由于XPS分析不能直接导致接枝在表面上的N-物质的性质（化学位移没有显著差异），因此进行化学衍生化。气相化学衍生化进行油模型聚合物，以评估反应性和选择性的每种试剂对每个预期的功能基团。结果表明，苯甲醛衍生物是很好的胺基团的衍生试剂，而溴是选择的试剂来定量的不饱和度。使用这些方法，发现表面上的胺和烯烃浓度根据等离子体处理时间增加，从50秒等离子体处理的3%的初始值上升到250秒等离子体处理的6%。原子力显微镜研究取向聚四氟乙烯薄膜也表明，发生链断裂的等离子体处理时间增加。因此，似乎确定的处理参数应该需要几个效果，如氮接枝，胺和烯烃的形成，和链断裂之间的最佳折衷。
A cylindrically configured plasma treatment system for Radio Frequency Glow discharges fed with ammonia was used to modify the internal surface of ePTFE arterial protheses to improve their biocompatibility. For a better understanding of the effects of this type of treatment oil the surface, RF-plasmas were also performed on PTFE films. The surface chemical composition was then characterized by XPS. The initial analyses showed that 15% of the surface atoms were replaced by nitrogen (N/C ratio of 0.3), whereas the F/C ratio decreased from 2 to 0.7-0.5 which indicates that the treated surfaces presented different chemical species, such as amine, imine, amide, acid groups, and insaturations. As XPS analyses could not lead directly to the nature of the N-species grafted on the surface (the chemical shifts being not significantly different), chemical derivatization was thus performed. Vapor phase chemical derivatization was carried out oil model polymers to evaluate the reactivity and the selectivity of each reagent toward each of the expected functional groups. The results indicate that benzaldehyde derivatives were good derivatizing reagents for amine groups, whereas bromine was the reagent of choice to quantify the insaturations. Using these methods, the amine and alkene concentrations on the surface were found to increase according to plasma treatment time rising from their initial value of 3% for a 50 s plasma treatment to 6% for a 250 s plasma treatment. AFM studies on oriented Teflon films also demonstrated that the Occurrence of chain breaking increased with plasma treatment time. It therefore appears that determining the treatment parameters should require the best compromise between several effects such as nitrogen grafting, amine and alkene formation, and chain breaking.