Synthesis of Specially Designed Adhesion Promoter for Grafting Polypyrrole



Summary: Adhesion of conducting polymers to the metal/metal oxide surfaces is not strong. An attempt was made to modify these reactive metal surfaces by N-derivatised pyrroles. ω-(pyrrol-1-yl alkyl) phosphonic acids with different chain lengths were successfully synthesized and characterized. These derivatives were studied for their adsorption and self-assembling phenomena onto Ti/TiO2, Ta/Ta2O5 and Al/Al2O3. Various analytical tools were used to characterize the modified surface. Contact angle measurements indicated an increase in hydrophobicity after adsorption that was further confirmed by Surface Plasmon Resonance (SPR). X-ray Photoelectron Spectroscopy (XPS) studies showed that the molecules are oriented in a fashion such that phosphonic acid group is attached to the metal surface and pyrrole is pointing away from the surface. The oxidation potential of these derivatives was higher than pyrrole as expected. Surface polymerisation was successfully attempted on the modified metal substrates. The polymerised surface was examined under Scanning Electron Microscope (SEM). The new compounds not only function as self-assembling molecules, they also exhibit a new class of reactive functionalized derivatives that can be used as monomers for polymerisation.