In situ investigation of surfactants’ effect onto electrochemical synthesis and properties of polyfurans

Polyfuran (PFu) films were electrochemically deposited onto gold electro-quartz crystal microbalance (EQCM) electrodes using acetonitrile (ACN)/LiClO₄ solvent-electrolyte in presence of dodecylbenzenesulfonic acid (anionic, DBSA) and polyethylene glycol sorbitan monolaurate (non-ionic, Tween 20) surfactants. The effect of surfactants on structural and conductivity properties of the polymer films was investigated using Fourier transform-infrared spectroscopy (FT-IR) and four-probe conductivity measurements. The doping effects of surfactants onto the properties of PFu were correlated with mass gain using in situ EQCM. The conductivity of PFu polymer was measured for PFu with no surfactant and for PFu in presence of two surfactants (Tween 20 and DBSA). Our data indicate that although a fast polymerization, a sharp shift in the frequency and mass changes of the polymer films as well as the highest recorded conductivity of 0.048 S cm⁻¹ were all obtained for the PFu/Tween 20-2 sample, significantly more PFu films formed with PFu/DBSA than with PFu/Tween 20 samples. We concluded that more PFu films can be obtained when an oxidant and an anionic surfactant (DBSA) are used than when an oxidant is used alone, or when an oxidant is used with a non-ionic surfactant (Tween 20). A part of an anionic surfactant can be incorporated into a PFu structure like an oxidant anion and can act as co-dopant.