Synthesis of Phosphorus-Containing Polyanilines by Electrochemical Copolymerization

In this study, the phosphonation of a polyaniline (PANI) backbone was achieved in an acid medium by electrochemical methods using aminophenylphosphonic (APPA) monomers. This was done through the electrochemical copolymerization of aniline with either 2- or 4-aminophenylphosphonic acid. Stable, electroactive polymers were obtained after the oxidation of the monomers up to 1.35 V (reversible hydrogen electrode, RHE). X-ray photoelectron spectroscopy (XPS) results revealed that the position of the phosphonic group in the aromatic ring of the monomer affected the amount of phosphorus incorporated into the copolymer. In addition, the redox transitions of the copolymers were examined by in situ Fourier-transform infrared (FTIR) spectroscopy, and it was concluded that their electroactive structures were analogous to those of PANI. From the APPA monomers it was possible to synthesize, in a controlled manner, polymeric materials with significant amounts of phosphorus in their structure through copolymerization with PANI.

The Redox and Optical Response of the Electrogrowth Film from a Mixture of 2,5-Bis[4-(p-Aminophenoxy)Phenylene]-1,3,4-Oxadiazole and Fluorene

Electrochemical copolymerization of 2,5-bis[4-(p-aminophenoxy)phenylene]-1,3,4-oxadiazole (Ox) with fluorene (Fl) was carried out via consecutive multisweep cyclic voltammetry. The electrogrowth process was conducted in the potential range between 0 and 1.8 V, at a scan rate of 50 mV/s. The FTIR spectroscopy was used to solve the issues concerning the way of monomers linkage in the copolymer structure. A deep investigation of the electrogenerated copolymer film characteristics was performed by scanning electron microscopy, UV-Vis and fluorescence spectroscopy, and cyclic voltammetry.

Electrochemical Polymerization of PEDOT–Graphene Oxide–Heparin Composite Coating for Anti-fouling and Anti-clotting of Cardiovascular Stents

ABSTRACT: In this study, a novel hemocompatible coating on stainless steel substrates was prepared by electrochemically copolymerizing 3,4-ethylenedioxythiophene (EDOT) with graphene oxide (GO), polystyrene sulfonate (PSS), or heparin (HEP) on SUS316L stainless steel, producing an anti-fouling (anti-protein adsorption and anti-platelet adhesion) surface to avoid the restenosis of blood vessels. The negative charges of GO, PSS, and HEP repel negatively charged proteins and platelets to achieve anti-fouling and anti-clotting. The results show that the anti-fouling capability of the poly(3,4-ethylenedioxythiophene) (PEDOT)/PSS coating is similar to that of the PEDOT/HEP coating. The anti-fouling capability of PEDOT/GO is higher than those of PEDOT/HEP and PEDOT/PSS. The reason for this is that GO exhibits negatively charged functional groups (COO−). The highest anti-fouling capability was found with the PEDOT/GO/HEP coating, indicating that electrochemical copolymerization of PEDOT with GO and HEP enhances the anti-fouling capability. Furthermore, the biocompatibility of the PEDOT coatings was tested with 3T3 cells for 1–5 days. The results show that all PEDOT composite coatings exhibited biocompatibility. The blood clotting time (APTT) of PEDOT/GO/HEP was prolonged to 225 s, much longer than the 40 s of pristine SUS316L stainless steel (the control), thus greatly improving the anti-blood-clotting capability of cardiovascular stents.

Development of an Ionic Quartz Crystal Microbalance (QCM) Sensors for the Detection of Na+ and K+ in Human Urine

In this study, we developed a quartz crystal microbalance (QCM) ionic sensor that can determine Na+ and K+ in human urine by the immobilization of crown ether as an ionic selector on a QCM electrode. In detail, –COOH was first introduced onto the QCM electrode surface by electrochemical copolymerization of thiophene and 3-thiopheneacetic acid, and then crown ether was introduced as an ionic selector onto the –COOH-modified QCM electrode by amide bond reaction. The prepared QCM ionic sensor was evaluated by FT-IR spectroscopy, SEM, contact angle, and cyclic voltammetry to confirm its successful fabrication. A prepared QCM ionic sensor with 4′-aminobenzo18-crown-6 adsorbed at 0.344 μg to K+ cation in this experiment. The Na+ cation was 0.360 mg in a human urine sample with a prepared QCM ionic sensor with 4′-aminobenzo-15-crown-5 and the K+ cation in a real human urine sample was 0.280 mg with a QCM ionic sensor with 4-aminobenzo18-crown-6, respectively. According to these results, the prepared QCM ionic sensor could be used to detection of sodium and potassium concentrations in human urine samples.