Composite Langmuir Monolayers and Langmuir−Blodgett Films from 16-Mer Polyaniline

Abstract

The formation of Langmuir monolayers and Langmuir−Blodgett films is reported for the first time for a polyaniline oligomer, 16-mer, that was mixed with cadmium stearate. The processibility of this oligomeric material was greatly improved as compared to the parent polyaniline, which allowed one to use common solvents like chloroform as the spreading solvent. Analogously to composite polyaniline monolayers, the stability and the transferability are found to depend on the 16-mer content in the composite film, with poor stability and low transfer ratios above 60% of 16-mer. Deposited Langmuir−Blodgett films were found to be undoped (or only weakly doped) since they were obtained from monolayers spread onto aqueous subphases (pH = 6.0). Uniform Langmuir−Blodgett (LB) deposition was confirmed by optical microscopy and UV−vis spectra whose intensity increased linearly with the number of layers deposited and also with the 16-mer content. Fourier transform infrared (FTIR) results revealed that cadmium stearate was...