Zhang Fengxiang, Srinivasan M P
Department of Chemical and Environmental Engineering, The National University of Singapore, Singapore.
Langmuir. 2004 Mar 16;20(6):2309-14. doi: 10.1021/la0354638.
The assembly of two aminosilanes on silicon dioxide surfaces is investigated in this work. It is found that for 3-aminopropyltrimethoxysilane (APS), a smaller concentration of the silane and trace amounts of water in the deposition medium, an optimum time, and a postdeposition thermal curing are necessary to obtain a high primary-amine content. By optimization of deposition conditions, uniform APS films with a primary-amine content of 88.6% were obtained. The dependence of the primary-amine content on the experimental parameters is related to the extent to which amines are lost to hydrogen bonding with each other or with the substrate surface. Whenp-aminophenyltrimethoxysilane (APhS) was used, the primary-amine content in the film reached 100% and the surface morphology was more uniform than that of APS films under the same conditions. This is attributed to the rigid phenyl component in APhS that reduces opportunities for hydrogen bonding. In a comparison of the immobilization capacities of the different aminosilane substrates for pyromellitic dianhydride (PMDA), it is observed that higher primary-amine content favors higher uptake, and the APhS film yields 100% PMDA coverage. We infer that primary-amine content could be a measure of the film morphology and accessibility of the substrate amine groups.
本工作研究了两种氨基硅烷在二氧化硅表面的组装情况。研究发现，对于3-氨丙基三甲氧基硅烷（APS），在沉积介质中硅烷浓度较低且含有痕量水的情况下，需要有一个最佳时间以及沉积后进行热固化，才能获得高伯胺含量。通过优化沉积条件，获得了伯胺含量为88.6%的均匀APS膜。伯胺含量对实验参数的依赖性与胺因相互之间或与基底表面形成氢键而损失的程度有关。当使用对氨基苯基三甲氧基硅烷（APhS）时，在相同条件下，膜中的伯胺含量达到100%，且表面形态比APS膜更均匀。这归因于APhS中刚性的苯基成分减少了形成氢键的机会。在比较不同氨基硅烷基底对均苯四甲酸二酐（PMDA）的固定能力时，观察到较高的伯胺含量有利于更高的吸附量，且APhS膜的PMDA覆盖率达到100%。我们推断伯胺含量可以作为膜形态和基底胺基团可及性的一种度量。
