| Abstract
| - Amorphous and nanocrystalline oxide films have been coated on the surface of a high-temperature polyimide composite (PMR-15). Solution-based titania (TiO2) deposition has been used to grow films up to 750 nm thick. The formation, degree of crystallinity and adherence of these coatings is controlled by the composition of the deposition medium and is influenced by the chemical composition of the polymer surface. In some cases, the oxide deposition solution caused partial hydrolysis of the polymer surface, which itself promoted adhesion of the titania film.
- The formation, degree of crystallinity, and adherence of dense titania (TiO2) thin film coatings on ahigh-temperature polyimide resin (PMR-15) can be influenced by the chemical composition of the polymersurface. Furthermore, solution deposition conditions can be adjusted to provide additional control overthe morphology and crystallinity of the titania films. Recipes for solution-based titania deposition thatused a slowly hydrolyzing titanium fluoride salt in the presence of boric acid as a fluoride scavengerallowed growth of films up to 750 nm thick in 22 h. By adjusting solution pH and temperature, eitheramorphous titania or oriented crystalline anatase films could be formed. Surface sulfonate groups enhancethe adhesion of solution-deposited oxide thin film coatings. While most sulfonation procedures severelydamaged the PMR-15 surface, the use of chlorosulfonic acid followed by hydrolysis of the installedchlorosulfonyl groups provided effective surface sulfonation without significant surface damage. In somecases, the oxide deposition solution caused partial hydrolysis of the polymer surface, which itself wassufficient to allow adhesion of the titania film through chelation of titanium ions by exposed benzoicacid groups on the polymer surface.
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