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以油酸为有机配体,采用两相方法合成了油溶性的超小尺寸纳米晶体nano ZrO_2,并对nano ZrO_2表面包覆的油酸改性使纳米晶体与聚酰胺酸(PAA)接枝,通过旋膜法热亚胺化后形成nano ZrO_2/聚酰亚胺(PI)复合超薄膜。利用TEM、XRD、FTIR和SEM等对nano ZrO_2及nano ZrO_2/PI复合超薄膜进行表征,并对nano ZrO_2/PI复合超薄膜的介电性能进行了探究。结果显示,nano ZrO_2尺寸均一(5.0nm左右),为锐钛矿晶型,其晶体结构和尺寸不受改性接枝影响。nano ZrO_2在复合超薄膜中分散良好。电学研究表明,复合超薄膜的介电性能受nano ZrO_2/PAA质量比及制膜热亚胺化温度影响。当PAA:ZrO_2质量比为2:3、热亚胺化温度为320℃时,介电常数达到最大,几乎是纯PI薄膜的2倍。两相法-改性接枝-热亚胺化制备PI复合超薄膜的方法简单高效、能够避免无机粒子在PI基体内的团聚并提高介电性能,对于PI基复合薄膜的制备、应用及推广具有重要意义。
Using oleic acid as organic ligand, the oil-soluble nanosize nanocrystalline nano ZrO 2 was synthesized by two-phase method. The nanocrystalline and polyamic acid (PAA) were grafted onto the surface of nano ZrO 2 modified by oleic acid. The nano ZrO 2 / polyimide (PI) composite ultrathin film was formed by spinodal thermal imidization. The nano ZrO 2 and nano ZrO 2 / PI composite thin films were characterized by TEM, XRD, FTIR and SEM, and the dielectric properties of nano ZrO 2 / PI composite thin films were also investigated. The results show that nano ZrO 2 is uniform in size (about 5.0 nm) and anatase, and its crystal structure and size are not influenced by modified grafting. nano ZrO 2 is well dispersed in the composite ultra-thin film. Electrical studies show that the dielectric properties of the composite ultrathin films are affected by the nano ZrO2 / PAA mass ratio and the thermal imidization temperature. When PAA: ZrO 2 mass ratio is 2: 3 and thermal imidization temperature is 320 ℃, the dielectric constant reaches the maximum, which is nearly double that of pure PI film. Two-phase method-modified grafting-thermal imidization method for preparing PI composite ultrathin films is simple and efficient, which can avoid agglomeration of inorganic particles in PI matrix and improve dielectric properties. The preparation, application and promotion of PI-based composite films It is of great significance.