用单体4,4′-二胺基二苯醚(ODA)和均苯四甲酸二酐(PMDA)添加纳米SiO2,在溶剂N,N-二甲基乙酰胺(DMAC)中,采用原位聚合法合成SiO2/聚酰亚胺(PI)复合薄膜。用氢氟酸刻蚀SiO2纳米粒子,引入纳米微孔,形成含有微孔的PI薄膜。造孔剂含量为15%时,薄膜的介电常数从纯聚酰亚胺的3.54降低至3.05(1kHz)。用透射电镜表征微孔结构,分析了微孔孔径和造孔剂(SiO2)含量对薄膜介电常数、耐热性、疏水性和机械强度等性质的影响。
SiO2/polyimide(PI) nanocomposite films with low dielectric permittivity with diamines of pyromellitic dianhydride(PMDA) and 4,4-oxydianiline(ODA) were successfully synthesized by a wet phase inversion process.Then removal of the silica cores of the nano-composite films by HF etching gives rise to the nanoporous of PI films.It is found that the dielectric permittivities of the porous films can be reduced from 3.54 of the pure PI to 3.05(1kHz) by using 15 wt% pore-former(SiO2).The nanopores were characterized by transmission electron microscopy(TEM).The relationships between the structure of the films and the properties,including the dielectric permittivity,the heat resistance,the contact angles and the mechanical strength,were researched.