自组装聚电解质薄膜的低角度X射线衍射研究

Low Angle XRD Study on Self-Assembled Polyelectrolyte Multilayer Films

采用静电自组装技术在单晶硅和石英玻璃基片上制备了阳离子聚电解质PDDA和阴离子聚电解质PS-119的多层复合薄膜,对薄膜作低角度X射线衍射分析,得到清晰的Kiessig衍射曲线,根据衍射曲线估算了薄膜的厚度。自组装PDDA/PS-119薄膜的层状结构特征不明显,聚电解质单层的厚度可以控制在1nm上下,双层的厚度可以控制在2nm左右,薄膜的总厚度与聚电解质水溶液的浓度有关,与薄膜的双层数成比例关系。

Multilayer thin films of poly(diallyldimethylammonium chloride) (PDDA) and polymeric dye S-119 (PS-119) were formed on silicon wafers and quartz substrates by using the electrostatic self-assembly technique, and were investigated by low angle X-ray diffraction. Kiessig fringes were observed on thediffractograms, and the thickness of the multilayer thin films was calculated. It seems there were no periodical layering structures existing within the thin films. The average thickness of a monolayer of PDDA or PS-119 was around 1nm, and that of a PDDA/PS-119 bilayer was around 2nm. The total thickness of the films was determined by the concentrations of the aqueous polyelectrolytes, and directly proportional to the bilayernumbers of the films.