Electroactivity of Electrochemically Synthesized Poly (Aniline Boronic Acid) as a Function of pH: Role of Self-Doping

The influence of pH on the electrochemical behavior of electropolymerized, self-doped poly(aniline boronic acid) thin films in the presence of D-fructose has been investigated with voltammetry and potentiometry in phosphate-buffered saline solution. It was found that the complexation of boronic acid with D-fructose and subsequent formation of self-doped polymer extends the electroactivity of poly(aniline boronic acid) to neutral and alkaline media in a manner similar to that of other self-doped polyanilines. However, the electroactivity exhibits more complex pH-dependent behavior, suggesting a transition between species involved in the self-doping process. Results obtained with in situ UV-vis spectroscopy and ex situ FTIR spectroscopy in conjunction with 11B and 19F NMR studies of monomeric species indicate that the selfdoped structure of poly(aniline boronic acid) is pH sensitive and that the anionic boronic acid complex involves either fluoride or hydroxide depending on pH