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

观察了单轴拉伸和银分散聚酰亚胺薄膜在可见光和近红外区的透射率各向异性。在6 ~ 25mol%硝酸银溶液中，通过热固化和同时单轴拉伸一步制得膜。在固化过程中，具有棒状结构的聚酰亚胺链沿拉伸方向取向，同时析出具有细长形状的纳米银颗粒。14.8μm厚的薄膜在850nm处，垂直拉伸方向透射率为80%，透射比各向异性大于320:1(25dB)，在150℃下退火1h后，其光学性能保持不变。这种薄膜满足了将薄膜偏振器插入硅基波导中形成的凹槽的所有要求。另一方面，采用含金属盐或有机金属配合物的聚酰胺酸热固化法制备了8种含金属（Au、Ag、Pd、Cu、Al、Co、Fe、Ni）的含氟聚酰亚胺薄膜。研究了金属颗粒的化学状态、平均尺寸和空间分布，并与宿主聚酰亚胺薄膜的热光学性能进行了比较。析出的金属颗粒增加了聚酰亚胺的平均折射率。所有薄膜在可见区域的透明度都比宿主聚酰亚胺低得多。而含金属薄膜除含金薄膜外，在近红外区域（1550nm处）透光率均高于80%。用磁场对六氟乙酰丙酮钴制备聚酰亚胺，观察到入射光的偏振旋转。这可以看作是含钴纳米粒子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.