【作者】 崔国良；

【导师】 马红钦；

【作者基本信息】 天津大学 ， 化学工程， 2006， 硕士

【摘要】 本文对碳纳米管和聚四氟乙烯超细颗粒进行活化处理,用分子自组装技术在金属表面制备复合粗糙表面,然后检测改性后表面的憎液性及抗结垢性能。首先,用酸洗法纯化碳纳米管,然后用高温酸氧化法活化碳纳米管。用透射电镜和X射线光电子能谱分析仪表征纯化、活化两种状态下的颗粒表面结构形貌和价键状态。实验结果表明,高温酸氧化法能有效活化并切短碳纳米管,使碳纳米管颗粒表面生成羧基等活性官能团。将表面抛光处理后的金属基片(银、铜)放在十六烷溶液中进行氨基十一酸分子连接,用扫描电镜和X射线光电子能谱分析仪对分子接枝后的金属表面形貌和价键状态进行表征,并选择连接性能较好的金属铜做进一步实验测试。在铜表面进行碳纳米管及PTFE超细颗粒的自组装,然后用扫描电镜和X射线光电子能谱分析仪表征自组装后表面的形貌和价键状态。实验结果表明,碳纳米管和聚四氟乙烯超细颗粒通过携带的羧基官能团与铜元素以配位化学键结合,强烈的吸附在基片表面。最后,用接触角测量仪检测基片表面在连接颗粒前后的润湿性变化,分析其原因;用扫描电镜表征自组装前后基片表面的结垢变化,研究其机理。实验结果表明:金属表面进行颗粒自组装后,其憎液性及抗结垢性能都有一定提高。自组装表面形成的低表面能薄膜和表面微/纳米结构,有效提高了基片表面的表面接触角,并且增大了在基片表面形成垢粒所需的自由能,减弱结垢倾向。改性后的表面有望应用于金属抗垢及强化传热等领域。更多还原

【Abstract】 Ultrafine polytetrafluoroethylene (PTFE) particles and carbon nanotubes (CNTs) were activated successfully and then were self-assembled on the metal surface. Both the anti-wetting and anti-fouling capability of modified material surface were characterized.First, the raw CNTs were purified by diluted nitric acid solution. Then, the purified CNTs had been activated by seething dense nitric acid solution for 4 hours. Transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS) were employed to characterize the purified and activated CNTs. The results indicate:the seething dense nitric acid solution could effectively break CNT particles and activate their surface. The carbonyl and carboxyl groups were formed on the CNT particles’surface after activated in the seething dense nitric acid solution.The 11-Aminoundecanoic acid [NH2(CH2)10COOH] molecules were grafted on the polished and activated metal surface in the cetane. Scanning electron microscopy (SEM) and XPS were employed to characterize the grafted metal surface. The most active metal surface was chosen for particles-grafting experiments.CNTs and PTFE particles were self-assembled on the copper surface which was characterized by SEM and XPS. The results indicate:CNTs and PTFE particles could combine with copper atom by the carboxyl groups and then adsorb on the copper surface intensively.In the end, the contact-angle measurement was employed to characterize the difference of wetting between the raw copper surface and the treated one; SEM was used to detect the change of anti-fouling capability before and after self-assembling treatment. The mechanism was then analyzed. The results indicate:After having been self-assembled, the anti-wetting and anti-fouling capabilities of copper surface were improved greatly. The self-assembled process could improve the contact-angle of the surface effectively, and debase the tendency of being fouling.Modified material surface can be used in many fields such as anti-fouling, anti-contamination and heat transfer enhancement.更多还原