Scanning probe characterization of Langmuir-Blodgett and self-assembled films of pyrrole derivatives

Atomic force microscopy was used to investigate the space molecular organization of Langmuir-Blodgett (LB) and self-assembled (SA) films of pyrrole derivatives on different substrates. The LB films were obtained from monomers of 3-hexadecyl-pyrrole (3HP); the polymerization of the film was performed directly at the air-subphase interface, and the films were collected on hydrophilic glass. Very homogeneous polymeric and monomeric LB films were collected on glass with a transfer rate near unity, the typical average roughness range was 0.9 ± 0.4 nm, and the quality of films was independent of the dipping speed. A functionalized molecule, 11-(3-pyrrolyl)undecyl mercaptane (3UPSH), was used to modify Ti and TiN electrodes by immersing the substrates in a solution containing the redox active molecule. The modification of the metal surfaces was proved by means of time of flight secondary ion mass spectrometry (TOF SIMS) and AFM characterization.