Silsesquioxane-urethane hybrid for thin film applications

Transparent polyurethane hybrid containing an inorganic open cage polyhedral oligomeric silsesquioxane was synthesized for thin film applications. The resulting material was characterized using various spectroscopic, microscopic, thermal, and scattering techniques. Modulated differential scanning calorimetry (MDSC) in conjunction with photoacoustic Fourier transform infrared spectroscopy (PA-FTIR) has enabled to probe the reaction and chemical structure of the hybrid. Si-29 solid-state nuclear magnetic resonance spectroscopy results prove the formation of the urethane hybrid. The evolution of the hybrid structure during the reaction was investigated using small-angle neutron scattering (SANS). The coating, when applied to clean steel substrates via dip coating, reveals a uniform, dense, and essentially defect-free morphology. Analysis by angle-resolved X-ray photoelectron spectroscopy (XPS) has allowed the interface between the substrate and the coating to be probed. It is found that the POSS-urethane coating forms a lamellar structure rather than a random 3D network.