Langmuir and Langmuir-Blodgett films of parent polyaniline doped with functionalized acids

The fabrication of Langmuir and Langmuir-Blodgett (LB) films from high-molecular-weight, doped parent polyaniline is reported. Parent polyaniline was rendered soluble by doping it with functionalized protonic acids (e.g. camphorsulfonic and toluenesulfonic acids) whose counter-ion induces solubility in low boiling point solvents such as chloroform. Condensed monolayers with high collapse pressures (above 30 mN/m) were obtained when an acidic subphase was used. The monolayers could be readily transferred onto hydrophilic substrates in the form of Z-type Langmuir-Blodgett films, and most importantly with transfer ratios close to 1. Interestingly, the films are readily obtained in the doped form and are electroactive.