Control of Dispersion and Shapes of Metallic Nano-particles Generated in Polymer-metal Complex Systems and Development of Functional Materials for Optical Devices.

在可见光和近红外区域的光学透射率的各向异性观察单轴拉伸和银分散的聚酰亚胺薄膜。该膜是在一个步骤操作，即热固化和同时单轴拉伸的聚酰胺酸膜溶解6银25mol%。具有棒状结构的聚酰亚胺链在固化过程中沿拉伸方向沿着取向，伴随着具有细长形状的银纳米颗粒的沉淀。薄膜厚度为14.8μ m，在850 nm处的各向异性透过率大于320：1（25 dB），垂直于拉伸方向的透过率为80%，经150°C退火1h后仍保持其光学性能。该薄膜满足插入硅基波导中形成的凹槽中的薄膜偏振器的所有要求。另一方面，通过热固化聚酰胺酸的金属盐或有机金属配合物，制备了八种含金属（Au，Ag，Pd，Cu，Al，Co，Fe，Ni）的含氟聚酰亚胺薄膜。金属粒子的化学状态，平均尺寸和空间分布进行了检查，并与那些主机聚酰亚胺的薄膜的热性能和光学性能进行了比较。沉淀的金属颗粒增加聚酰亚胺的平均折射率。所有的膜显示出在可见光区的透明度比主机聚酰亚胺少得多。然而，除了含金的膜之外，含金属的膜在近红外区域（在1550 nm处）显示出高于80%的透射率。用六氟乙酰丙酮钴（Hacacacetylacetonate）为原料，在磁场作用下制备聚酰亚胺，观察到入射光偏振的旋转。这可以被认为是由含钴纳米颗粒引起的光学法拉第效应。

Anisotropy in optical transmittance in the visible and near-infrared region was observed for uniaxially drawn and silver-dispersed polyimide films. The films were prepared in a one step operation, that is thermal curing and simultaneous uniaxial drawing of poly(amic acid)films dissolving 6〜25mol% of silver nitrate. The polyimide chains having a rod-like structure were oriented along the drawing direction during curing accompanying with the precipitation of silver nano-particles having elongated shapes. An anisotropy in transmittance of larger than 320 : 1(25dB)was obtained for a 14.8μm-thick film at 850nm with an transmittance of 80% perpendicular to the drawing direction, and its optical properties were retained after annealing at 150°C for 1h. This film suffices all the requirements for a thin-film polarizer inserted into a groove formed in silica-based waveguides. On the other hand, eight kinds of metal(Au, Ag, Pd, Cu, Al, Co, Fe, Ni)containing fluorinated polyimide films were prepared by thermal curing of poly(amic acid)s containing metallic salts or organo-metallic complexes. The chemical states, average sizes, and spatial distribution of the metallic particles were examined, and the thermal and optical properties of the films were compared with those of the host-polyimide. The precipitated metal particles increase the averaged refractive indices of the polyimides. All the films showed much less transparency in the visible region than the host-polyimide. However, the metal-containing films, except for the gold-containing film, showed transmittance higher than 80% in the near-infrared region(at 1550nm). Rotation of polarization of incident light was observed for a polyimide prepared from cobalt(hexafluoroacetylacetonate)by applying a magnetic field. This can be regarded as the optical Faraday effect caused by cobalt-containing nano-particles.