New siloxane-organic polyesters with azobenzene side chains.: Synthesis, thermotropic behavior and surface properties

New siloxane-organic polyesters, bearing azotype units in the side chain, were synthesized by direct solution polycondensation at room temperature, starting from 2,2-[4-[(4-nitrophenyl)azolphenyl]iminobisethanol (Disperse Red 19) and different siloxane diacids, using dicyclohexylcarbodiimide as an activator and 4-(N,N-dimethylamino)pyridinium-p-toluenesulfonate as the catalyst. The structure of the obtained polyesters was confirmed by H-1 and C-13 NMR as well as IR spectroscopy. The molecular weight and polydispersity were estimated by GPC. The thermotropic behavior was investigated by POM, DSC and TOA. The surface composition was determined by ESCA (XPS) analysis and proved enrichment in silicon for all samples. All compounds show good solubility in common organic solvents.