Acid Electrolytes Effect on In-Situ Growth and Morphology of Polymer Nanowires in Microelectrode Devices

摘要

We investigated five acids-(1) formic acid, (2) acetic acid, (3) perchloric acid, (4) hydrochloric acid and (5) nitric acid-as an electrolyte for a direct one-step, in-situ electrochemical growth of conducting polyaniline (CPA) nanowires onto patterned microelectrode devices (MEDs). The effect of these acid electrolytes on the growth and morphology of CPA nanowires generated from its monomer aniline solution in acid electrolytes are reported. We investigated acid electrolyte solutions with varying concentrations (0.2-1.0M) and monomer aniline solutions (concentrations: 0.1-1.0M). The growth of CPA nanowires was not observed in either formic or acetic acid electrolyte solutions at any monomer aniline and acid electrolyte concentrations. Neither formic nor acetic acids facilitated electro-polymerization processes. This may be due to their weak acid behavior. Growth of CPA nanowires was observed from all inorganic (perchloric, hydrochloric and nitric) acids with aniline concentrations of 0.1-0.6M and electrolyte concentrations of 0.2-0.6M in various degrees. High quality CPA nanowires with diameters ~50-150nm and length ≥2μm and high surface-area porous nano-network morphologies were obtained from 0.2-0.4M aniline solutions in 0.2-0.4M nitric and 0.2-0.6M perchloric acid electrolyte solutions. These high qualirty CPA nanowires will facilitate their use in chemical sensor and biosensor applications with improved detection capability.