Preparation and characterization of green reflective films of polyaniline analogs containing azobenzene units |
| |
Authors: | Hikaru Yamada Minoru Kukino Zhi An Wang Ryo Miyabara Nobutaka Fujimoto Junpei Kuwabara Kiyoto Matsuishi Takaki Kanbara |
| |
Affiliation: | 1. Tsukuba Research Center for Interdisciplinary Materials Science (TIMS), Graduate School of Pure and Applied Science, University of Tsukuba, Tsukuba, Japan;2. Sumitomo Seika Chemicals Co., Ltd., Shikama‐ku Himeji, Japan;3. Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan |
| |
Abstract: | Pd‐catalyzed polycondensation of aniline derivatives and 4,4′‐dibromoazobenzene affords polyaniline analogs containing azobenzene units. The polymers are red in solution and in thin films state, whereas they have a green luster in thick films. Substitution of 4,4′‐dibromoazobenzene for 4,4′‐dibromostilbene changes the reflection color from green to blue, whereas the introduction of a non‐conjugated unit slightly affects the reflection color. The glossiness of the film is dependent on the smoothness of the film surface. The reflectance measurements using polarized light reveal that reflection spectra correlate well with the complex refractive index (ñ = n + ik) of the film. These results confirm that the green luster can be attributed to the uniform surface reflection of the object, which has a large refractive index and absorption coefficient at around 500 nm. The polymer films exhibit good transmission of radio frequency signals owing to the lack of free electron carriers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41275. |
| |
Keywords: | films coatings dyes/pigments optical properties polycondensation |
|
|