纳米界面作用下等离子体改性时效性的正电子研究

项目名称： 纳米界面作用下等离子体改性时效性的正电子研究

项目编号： No.11205118

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学II

项目作者： 陈喆

作者单位： 武汉工程大学

项目金额： 25万元

中文摘要： 膜分离技术是最具发展潜力的水处理方法。为得到同时具有较高截留特性和纯水通量的高分子膜，需提高膜表面的亲水性。等离子体技术能快速高效的改善高分子膜表面的亲水性，但该性能会随时间的推移而衰减。这种时效性问题是制约等离子体技术在高分子膜表面功能化的主要瓶颈。 本项目以乙烯-醋酸乙烯酯共聚物（EVA）为研究对象，在材料中构筑不同类型的纳米界面，利用等离子体改善纳米复合膜表面的亲水性，借助慢正电子束技术监控膜表面亲水性的极性基团其迁移行为，根据正电子寿命谱学结果，探究自由体积特性与等离子体处理时效性的关系，并从分子链段运动的微观角度阐明时效性的机理及其影响因素。 本项目旨在利用正电子技术揭示纳米界面对等离子体表面改性的时效性的影响机理，从而可通过改变材料的纳米结构来调控时效性的强弱，调控材料的表面性能，进而为高分子膜表面功能化的开发提供理论支撑，为推动水处理技术的发展奠定基础。

中文关键词： 分离膜；正电子湮没；高分子；界面；纳米结构

英文摘要： The clean, fresh water in the world is not enough for all the uses, whether agricultrue, industrial or domestic, but the water demand continues to rise due to the increase of population. Membrane separation is a novel technique, which can be used for obtaining fresh water from sea water, saline water and so on. In order to develop the membrane exhibiting even better performance (higher water flux), the hydrophilicity of the membrane surface need to be improved. Plasma modification is a unique method to improve the surface properties of non-polar polymers, but the improved properties usually decay with storage time which is called as the durability of plasma modification. In this work, EVA nanocomposites with different nano-interfaces are prepared, and the nanocomposite surfaces are modified by plasma. Positron lifetime annihilation measurement is utillized to probe the free-volume hole in the nanocomposites. The correlation between the free volume property and the durability of the surface wettabiliy is to be studied. Positron annihilation gamma ray spectroscopy coupled with positron beam is applied to monitor the movement of the polar group in EVA nanocomposite surface after plasma modification. According to the effect of the nano-interface on the durability of the plasma modification, which is explained

英文关键词： seperation membrane；positron annihilation；polymer；interface；nanostructure