Flexible, optically transparent, high refractive, and thermally stable polyimide–TiO2 hybrids for anti-reflection coating

• Published in: RSC advances Vol. 3; no. 38; pp. 17048 - 17056
• Main Authors: Yen, Hung-Ju, Tsai, Chia-Liang, Wang, Pei-Hsuan, Lin, Jiang-Jen, Liou, Guey-Sheng
• Format: Journal Article
• Language: English
• Published: 2013
• Subjects: coatings; dimensional stability; films (materials); moieties; refractive index; thermal stability; titanium; titanium dioxide; transmission electron microscopy; X-ray diffraction
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c3ra42180e

In this study, flexible and transparent polyimide–nanocrystalline-titania hybrid optical films with a high titania content (up to 50 wt%) and thickness (15 μm) were prepared from new soluble poly(o-hydroxy-imide)s and fabricated for a three-layer antireflection coating. The hydroxyl groups on the backbone of the polyimides could provide a reaction site for organic–inorganic bonding and resulted in homogeneous hybrid solutions by controlling the mole ratio of titanium butoxide/hydroxyl groups. The well-dispersed nanocrystalline-titania was demonstrated by XRD and TEM measurements. The flexible hybrid films with good surface planarity, thermal dimensional stability, tunable refractive index (1.63–1.80 at 633 nm), and high optical transparency were successfully obtained and further utilized to prepare a three-layer anti-reflection coating, indicating its potential optical applications.