Puniredd Sreenivasa Reddy, Srinivasan M P
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive, 4117576 Singapore.
J Colloid Interface Sci. 2007 Feb 1;306(1):118-27. doi: 10.1016/j.jcis.2006.09.051. Epub 2006 Sep 23.
Ultrathin films containing dendrimers are fabricated on amine- and anhydride-derivatized silicon dioxide surface through alternate layer-by-layer (LbL) assembly of pyromellitic dianhydride (PMDA) and poly(amidoamine) (PAMAM) dendrimer in supercritical carbon dioxide (SCCO2) with interlayer linkage established by covalent bonds. X-ray photoelectron and UV-visible absorption spectroscopies, atomic force microscopy (AFM), and ellipsometry were employed to study the interfacial chemistry, growth, morphology, and thickness of the assembled film. XPS analysis suggests that the PMDA/PAMAM interlayer covalent bond is established to completion, and functional surfaces for immobilization of the next layer are available after deposition of each layer. UV-visible absorption and ellipsometry revealed layer-by-layer growth of the film. The functional property film as a porous matrix was manifested in the reduction of the refractive index upon introduction of the dendrimer.
通过在超临界二氧化碳（SCCO2）中对均苯四甲酸二酐（PMDA）和聚（酰胺胺）（PAMAM）树枝状大分子进行交替逐层（LbL）组装，并通过共价键建立层间连接，在胺和酸酐衍生化的二氧化硅表面制备了含有树枝状大分子的超薄膜。采用X射线光电子能谱和紫外可见吸收光谱、原子力显微镜（AFM）和椭偏仪研究了组装膜的界面化学、生长、形态和厚度。XPS分析表明，PMDA/PAMAM层间共价键已完全形成，每层沉积后都有用于固定下一层的功能表面。紫外可见吸收光谱和椭偏仪显示了膜的逐层生长。作为多孔基质的功能特性膜在引入树枝状大分子后表现为折射率降低。
