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 B-11 and F-19 NMR studies of monomeric species indicate that the self-doped structure of poly(aniline boronic acid) is pH sensitive and that the anionic boronic acid complex involves either fluoride or hydroxide depending on pH.