| Attributs | Valeurs |
|---|
| type
| |
| Is Part Of
| |
| Subject
| |
| Title
| - Effects of Molecular Structures on the Near-Infrared Optical Propertiesof Polyimide Derivatives and Their Corresponding Optical Waveguides
|
| has manifestation of work
| |
| related by
| |
| Author
| |
| Abstract
| - Polyimides have been demonstrated to be a potential candidate as optical waveguidematerials. Previous studies were focusing on the reducing the optical loss by decreasing the C−H bondingdensity of the molecular structure. The tuning of the near-infrared (NIR) overtone absorption positionfrom the polarizability of the bridge group in polyimides is rarely studied. In this study, a series ofpolyimides prepared from pyromellitic dianhydride (PMDA) and diamines with various bridge groupswere used to investigate the structure−NIR optical property relationships. The bridge groups include−SO2−, −S−, −O−, and −CH2−. Both the experimental and ab initio calculation on the model compoundsand polyimide derivatives revealed that the stronger the electron-withdrawing ability of the neighboringbridge group, the shorter the aromatic C−H bond length. This results in the shifting of the overtonefrequencies of the C−H bond to higher frequencies. Such bridge effects played an important role in theoptical loss of the corresponding polyimide waveguides. It was found that the optical loss was resultedfrom both the C−H bonding density and the shifting of the overtone absorption by the bridge group. Itindicates that tuning of NIR optical loss from the molecular structures of polyimides could be achieved.
|
| article type
| |
| is part of this journal
| |
