Effects of backbone configuration of polysilanes on nanoscale structures formed by single-particle nanofabrication technique
Effects of backbone configuration of polysilanes on nanoscale structures formed by single-particle nanofabrication technique
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DOI：
10.1021/ma051821x
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发表时间：
2005-11-29
期刊：
影响因子：
5.5
通讯作者：
Kohyama, A
中科院分区：
文献类型：
--
作者：
Seki, S;Tsukuda, S;Kohyama, A
离子束辐照聚甲基苯基硅烷（PMPS）可引起交联反应，形成具有规则长度和厚度的圆柱形纳米结构的聚合物凝胶。聚合物分子交联的空间分布受离子轨道中沉积能量密度的支配。剂量沿各离子径迹的径向变化导致形成半径为1 ~ 12 nm的圆柱形结构。这些圆柱形结构在原子力显微镜下很好地显示为蠕虫状结构（纳米线）。交联聚合物凝胶的总体积可以用这种圆柱形径向变化的交联分布很好地表示。针对传统聚合物凝胶统计理论估计的交联反应效率高估了聚合物链长对效率的依赖，推导了考虑纳米线尺寸与链长、离子束线性能量传递、离子轨迹径向剂量分布和聚合物整体链构型的关系的交联反应新形式。所得模型提供了一个更好的离子束诱导凝胶聚合物的表示。目前的结果也证明了这种技术在亚纳米空间分辨率的单粒子纳米结构制造中的潜在效用。
Ion-beam irradiation of poly(methylphenylsilane) (PMPS) is shown to cause cross-linking reactions, leading to the formation of a polymer gel containing cylindrical nanostructures of regular length and thickness. The spatial distribution of cross-links of polymer molecules is found to be governed by the deposited energy density in an ion track. The radial variation in dose along each ion track results in the formation of cylindrical structures with a radius of 1-12 nm. These cylindrical structures are well visualized by atomic force microscopy as wormlike structures (nanowires). The total volume of the crosslinked polymer gel can be represented by this cylindrical radially varying scheme of cross-link distribution well. As the cross-linking reaction efficiency estimated by conventional statistical theories of polymer gelation overestimate the dependence of the efficiency on the chain length of the polymers, a new formalism is derived considering the dependence of the nanowire size on the chain length, the linear energy transfer of the ion beam, the radial dose distribution in ion tracks, and the global chain configuration of polymers. The resultant model provides a better representation of ion-beam-induced gelation of polymers. The present results also demonstrate the potential utility of this technique for single-particle fabrication of nanostructures with subnanometer spatial resolution.