Topographical nanostructure patterning on the surface of a thin film of polyurethane containing azobenzene moiety using the optical near field around polystyrene spheres
Topographical nanostructure patterning on the surface of a thin film of polyurethane containing azobenzene moiety using the optical near field around polystyrene spheres
复制标题
DOI：
10.1021/ma0102870
复制
发表时间：
2001-10-09
期刊：
影响因子：
5.5
通讯作者：
Kawata, Y
中科院分区：
文献类型：
--
作者：
Hasegawa, M;Ikawa, T;Kawata, Y
利用聚苯乙烯（PS）球周围产生的光学近场诱导聚合物链迁移，在偶氮苯功能化聚氨酯薄膜表面形成了缩进纳米结构。将直径为98 ~ 990 nm的PS球通过自组织工艺排列在光响应聚合物薄膜表面，然后将薄膜暴露在488 nm的线偏振Ar+激光下。在原子力显微镜下，在聚氨酯表面观察到反映球体原始几何形状和排列的六角形压痕阵列。所形成的缩进结构的分辨率约为95 nm。这种结构在室温下是稳定的，并且可以通过加热薄膜超过其玻璃化转变温度（T,）来消除。形成凹痕的修改深度和直径取决于原PS球的大小。特别是直径大于505 nm的PS球，由于其产生的光学透镜效应，形成了更深的凹痕，并且用线偏振光照射直径大于505 nm的球，引起聚合物膜表面的各向异性修饰。聚合物膜的厚度对凹痕的改性深度有显著影响。我们制备了三种不同的光反应聚氨酯，每一种都含有稍微不同的偶氮苯部分。尽管这些聚合物实际上都具有相同的分子量、Tg和在辐照光波长下的吸收率，但观察到的每一种薄膜的凹痕深度却大不相同。此外，由于偶氮苯部分的反-顺-反异构化行为不同，观察到辐照光强度与可实现凹痕大小之间存在依赖关系。
An indented nanostructure was formed on the surface of azobenzene-functionalized polyurethane thin films by the induced migration of polymer chains using the optical near field generated around polystyrene (PS) spheres. The PS spheres, which had a diameter ranging from 98 to 990 nm, were arranged on the surface of a photoresponsive polymer film using a self, organization process, and the films were then exposed to a linearly polarized Ar+ laser at 488 nm. A hexagonal array of indentations reflecting the original geometry and arrangement of the spheres was observed on the polyurethane surface by atomic force microscopy. The indented structure that was formed had a resolution of similar to 95 nm. This structure was stable at room temperature and could be erased by heating the films above their glass transition temperature (T,). The modification depth and diameter of the dents formed depended on the size of the original PS spheres. In particular, deeper dents were formed by using PS spheres with a diameter of over 505 nm, due to the optical lens effect they created, and the irradiation onto spheres of greater than 505 nm diameter with linearly polarized light induced an anisotropic modification on the surface of the polymer films. The thickness of the polymer film significantly affected the modification depth of the dent. We prepared three different kinds of photoresponsive polyurethane, each containing a slightly different azobenzene moiety. Although these polymers all had virtually the same molecular weight, Tg, and absorptivity at the wavelength of the irradiated light, the modified depth of the dent observed for each of the films was very different. Furthermore, a dependence between the irradiated light intensity and the size of dent achievable was observed, which was due to the difference in the trans-cis-trans isomerization behavior of the azobenzene moiety.