“…In recent years, poly(o-phenylenediamine) (PoPD), as one of the most interesting polyanilines, has been proven to be used as a functional polymer in many studies due to its positively charged surface, homogeneity in electrochemical deposition and strong adherence to electrode surface (Turkmen et al, 2014;Wen et al, 2014;Duan et al, 2013;Khan and Ab Ghani, 2012). In addition, PoPD film could yield an interface with amino groups for the subsequent assembly of noble metal nanoparticles to enhance the conductivity (Turkmen et al, 2014;Kong et al, 2013;Zeybek et al, 2012;Zeybek et al, 2014). Among the noble metallic nanomaterials, gold nanoparticles (AuNPs) have become the most widely used due to its advantages of easy synthesis, low cost, good biocompatibility and ability to be readily modified by various chemical methods (Daniel and Astruc, 2004;Ghosh et al, 2008).…”