低介电常数聚喹啉衍生物薄膜的合成与表征

采用等离子体聚合技术合成了一种新型的低介电常数聚喹啉衍生物薄膜: 聚3-氰基喹啉(PP3QCN)薄膜. 借助于傅里叶变换红外光谱(FT-IR)、紫外-可见(UV-Vis)吸收光谱、X光电子能谱(XPS)和原子力显微镜(AFM)对薄膜结构进行了系统表征. 结果表明, 等离子体聚合条件对沉积膜的化学结构、表面组成、膜形态以及介电性能均有影响. 在较低的等离子体放电功率(10 W)条件下, 可得到具有较高芳环保留率和较大π-共轭体系的高质量聚3-氰基喹啉薄膜材料; 而在较高功率(25 W)条件下, 聚合过程中会出现比较严重的单体分子破碎, 形成较多非π-共轭体系的聚合物, 从而导致聚3-氰基喹啉的共轭度降低. 聚3-氰基喹啉薄膜的介电性能测试结果表明, 低放电功率(10 W)条件下制得的聚3-氰基喹啉薄膜具有比较低的介电常数值, 仅为2.45.

Synthesis and Characterization of a Polyquinoline Derivative Thin Film with a Low Dielectric Constant

We prepared a novel plasma polyquinoline derivative thin film, plasma-polymerized 3-cyanoquinoline (PP3QCN). Fourier transform infrared spectroscopy (FT-IR), UV-visible (UV-Vis) absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) characterization revealed that the plasma polymerization conditions affected the chemical structure, surface composition, morphology, and dielectric property of the plasma-deposited films. A smooth and homogenous PP3QCN film with a large π-conjugated system and a high retention of the aromatic ring structure of the monomer was obtained at a low discharge power of 10 W. At 25 W, more severe monomer molecular fragmentation was apparent during the plasma polymerization and thus the conjugation length of the PP3QCN films decreased because of the formation of a non-conjugated polymer. A low dielectric constant of 2.45 was obtained for the as-grown PP3QCN thin film deposited at 10 W.