Fine-tuning electrochemical properties of poly (3-aminophenylboronic acid) via optimization of electrodeposition

The electrochemical behaviour of electropolymerized poly (3-aminophenylboronic acid) [P(3-APBA)] is strongly dependent on the conditions under which it is formed. However, a systematic understanding of how electropolymerization parameters collectively govern the electrochemical properties of P(3-APBA) remains limited. In this work, the influence of electrolyte composition, supporting electrolyte concentration, fluoride concentration, monomer concentration, and electrodeposition parameters on the formation and electrochemical characteristics of P(3-APBA) films was systematically investigated. Polymer films were synthesized in hydrochloric acid (HCl), sulfuric acid (H2SO4), and phosphate-buffered saline (PBS) using cyclic voltammetry under controlled potential windows, scan rates, and deposition cycles. The resulting materials were characterized using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS), while ultraviolet-visible (UV-Vis) and Fourier Transform infrared (FTIR) spectroscopies confirmed polymer formation. The results show that electrolyte chemistry strongly influences polymer growth and electroactivity, with 0.5 M HCl producing films that exhibited the highest electroactive charge and the most defined redox transitions. In contrast, PBS-based systems showed significantly reduced electrochemical response, indicating suppressed charge transport and limited electroactive site accessibility. The monomer-to-fluoride ratio of 0.04:0.08 M was found to provide optimal balance between polymer formation and electrochemical performance, while a potential window of −0.1–1.0 V, an end potential of 0.5 V, and a scan rate of 20 mV/s promoted stable film growth. EIS analysis further revealed reduced charge-transfer resistance (Rct) under optimized conditions, consistent with enhanced electron-transfer kinetics within the polymer film. Collectively, these results demonstrate that electrolyte environment, fluoride-assisted activation, and deposition parameters act synergistically to govern the electrochemical properties of P(3-APBA), establishing a reproducible framework for controlled electropolymerization and electrochemical evaluation of this conducting polymer system.