Reactions of Zirconium (IV) n-Propoxide with SiH-Functional Polysiloxanes as a Route to Siloxane-Zirconium Hybrid Materials with Enhanced Refractive Index

The reaction of poly(hydromethylsiloxane-co-methylphenylsiloxane) with zirconium (IV) n-propoxide in dry toluene leads to extensive scission of the siloxane chain and conversion of Si-H groups. These processes produce oligomeric siloxanes and organosilanes containing moisture sensitive propoxy and siloxy-zirconate groups. The obtained post-reaction solution of zirconium containing heterosiloxane oligomers is stable under anhydrous conditions for several weeks. However, its exposure to moisture initiates the hydrolytic condensation of the reactive groups leading to cross-linking and the formation of a siloxane-zirconium composite. Spin coating of the siloxane-zirconium prepolymer followed by exposure to moisture produces thin films with excellent light transparency and increased refractive index. The final coatings are characterized by ellipsometry, UV-Vis, IR, and Si-29 MAS NMR spectroscopies.

Automated summary

The reaction between poly(hydromethylsiloxane-co-methylphenylsiloxane) and zirconium (IV) n-propoxide in dry toluene results in the formation of a siloxane-zirconium composite. The post-reaction solution containing heterosiloxane oligomers is stable under anhydrous conditions, but exposure to moisture leads to cross-linking and the formation of thin films with excellent light transparency and increased refractive index. The coatings are characterized using ellipsometry, UV-Vis, IR, and Si-29 MAS NMR spectroscopies.