Fabrication of multilayer thin films via metal–macromolecular ligand complexation

Layer-by-layer complexation of macromolecular ligands employing lanthanide metal ions was developed as a new technique to fabricate multilayer thin films. Poly(3-thiophene acetic acid) [PTAA] was prepared as a macromolecular ligand and was successfully used in the fabrication of self-assembled multilayer films by alternatively dipping desired substrates in aqueous polymer and Eu3+ ion solutions. The multilayer deposition was monitored by the absorbance increase due to polymer using UV–Visible spectrophotometer. The effect of process parameters including temperature, concentration and pH of the solutions were studied to understand and to optimize the multilayer thin film characteristics. The pH of the polymer solution has dramatic influence on the thickness of the multilayer film; absorption of film increased with increase in pH of the solution. The effect of process variables on the absorbance of the deposited multilayer was explained based on the conformational changes of polymer segments.