预处理浸泡对聚酰亚胺重离子微孔膜蚀刻的影响

Effect of soaking on etching of polyimide heavy-ion microfiltration membranes

聚酰亚胺(Polyimide,PI)膜是一种新型的有机膜,具有耐高温、耐强酸和耐辐射等特性,用其制备的重离子微孔膜可以用于电池隔膜和放射性废气过滤等特殊领域。应用中国原子能科学研究院HI-13串列加速器产生的重离子束32S离子轰击25?m的PI薄膜,再对薄膜进行化学蚀刻处理,使由重离子辐照损伤产生的径迹形成微孔。为改善微孔质量,在化学蚀刻前采用具有强氧化性溶液对PI膜进行预处理浸泡,系统分析了常温下采用高锰酸钾和双氧水两种溶液浸泡不同时间对PI膜化学蚀刻的影响。实验结果显示,预处理浸泡可明显加快PI膜的径迹蚀刻速率,缩短蚀刻时间,减小微孔的锥角和提高PI重离子微孔膜的蚀刻质量。

Background： Polyimide （PI） film is a new type of organic film possessing properties of high temperature resistance, acid resistance and radiation resistance, etc. The heavy-ion microporous membrane prepared by polyimide film can be used for battery diaphragm, radioactive waste gas filtering and other special areas. Purpose： This study aims to improve the quality of PI heavy-ion micro-filtration membrane by soaking pretreatment. Methods： First of all, 25-~tm PI films were irradiated by 32S ions produced by HI-13 tandem accelerator in China Institute of Atomic Energy to break the polymer chains. Latent tracks were created along the track of the ions. Then soaking pretrestment with two types of strong oxidizing solutions, i.e., potassium permanganate and hydrogen peroxide, was conducted before the chemical etching processing to form the micropores. Finally, etching time and the quality of micropores were compared and analyzed. Results： The etching rate for PI film pre-processed by soaking in potassium permanganate solution and hydrogen peroxide solution for 2 h are 1.6 times and 1.3 times respectively, compared with that no soaking pretreatment at normal temperature. More narrow cone angle is formed for faster etching rate. Conclusion： The experimental results showed that soaking pretreatment can obviously increase the track etching rate of PI membrane, decrease etching time, narrow the cone angle of pores and improve the quality of PI heavy-ion microporous membrane.