Facile synthesis of oxidative copolymers from aminoquinoline and anisidine

Enzymatic synthesis of 5-amino quinoline oligomers and evaluation of their free radical scavenging activity

The compound 5-aminoquinoline (AQ) was treated with horseradish peroxidase (HRP) and H2O2 in a reaction medium containing a dioxane:phosphate buffer mixture (70:30). Products (OAQ) with a degree of polymerization ranging from 4 to 12 were obtained. 1H NMR, FTIR, UV–vis, SEM, TG–DTA, DSC, XRD analysis, and conductivity measurements were conducted for characterization of OAQ. Compared with a monomer, OAQ showed higher thermal stability. After heating to 1000 °C, 46% of the initial weight of the OAQ remained. The antioxidant efficiencies of the monomer and oligomer were evaluated by the typical spectrophotometric method such as the bleaching of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. OAQ showed improved DPPH activity compared with the AQ monomer.

Carbon nanotube chemiresistor for wireless pH sensing

The ability to accurately measure real-time pH fluctuations in-vivo could be highly advantageous. Early detection and potential prevention of bacteria colonization of surgical implants can be accomplished by monitoring associated acidosis. However, conventional glass membrane or ion-selective field-effect transistor (ISFET) pH sensing technologies both require a reference electrode which may suffer from leakage of electrolytes and potential contamination. Herein, we describe a solid-state sensor based on oxidized single-walled carbon nanotubes (ox-SWNTs) functionalized with the conductive polymer poly(1-aminoanthracene) (PAA). This device had a Nernstian response over a wide pH range (2–12) and retained sensitivity over 120 days. The sensor was also attached to a passively-powered radio-frequency identification (RFID) tag which transmits pH data through simulated skin. This battery-less, reference electrode free, wirelessly transmitting sensor platform shows potential for biomedical applications as an implantable sensor, adjacent to surgical implants detecting for infection.

Polyaniline and poly(m‐toluidine) prepared by inverse emulsion pathway as corrosion inhibitors in surface coatings

Purpose

The purpose of the paper is to examine the synthesis of polyaniline (PAn) and poly(m‐toluidine) (PmT) via an inverse emulsion polymerisation pathway and evaluate of the synthesised polymers as corrosion inhibitors for steel protection in surface coatings.

Design/methodology/approach

PAn and PmT were prepared by inverse emulsion polymerisation using ammonium persulphate as an initiator and sodium dodecylbenzene sulphonate (SDBS) as an emulsifier. Spectrophotometric measurements were conducted to characterise the prepared polymers. Latex paint formulations were prepared and dry paint films were evaluated for their physical, mechanical and corrosion protection performance.

Findings

The prepared conducting polymers of PAn and PmT are good candidates for enhancing the corrosion protection of steel. They showed good performance as corrosion inhibitors in latex paints without bad side effects on the physico‐mechanical properties of paint films.

Practical implications

Recent advances in corrosion protection of steel by coatings via inverse emulsion polymerisation of aniline and m‐toluidine have improved performance of anti‐corrosive water‐borne paints. Using formulations based on this new technology, offer uncompromised high performance eco‐friendly anti‐corrosive water‐borne systems that answer the future industrial demands from the economical and environmental points of view.

Originality/value

PAn and PmT prepared by inverse emulsion polymerisation showed promising results as corrosion inhibitors for steel protection. The polymerisation process was conducted in water (emulsion polymerisation) and the polymer lattices were incorporated in water borne paints from ecological and economical points of view.

Simple Synthesis of Aminoquinoline/Ethylaniline Copolymer Semiconducting Nanoparticles

Pure copolymer nanoparticles from 8-aminoquinoline (AQ) and 2-ethylaniline (EA) were easily synthesized by a chemically oxidative polymerization in three different aqueous media. The potential and temperature of polymerization solution were used to successfully follow the polymerization progress. The molecular and morphological structures of the resulting AQ/EA copolymer particles were systematically characterized by IR, UV/Vis, NMR, gel permeation chromatography, laser particle-size analysis, atomic force and transmission electron microscopy. The oxidation potential of the monomers as well as the polymerization yield, structure, and properties of the particles were found to significantly depend on AQ/EA ratio, polymerization temperature and medium. It is surprisingly found that AQ homopolymerization and AQ/EA (50:50) copolymerization at 5 degrees C in HCl simply afford nano-ellipsoids with the major/minor axis diameters of 24/14 nm and 80/67 nm, respectively. A simple method of synthesizing semiconducting pure nanoparticles by introducing the AQ units with positively charged quaternary ammonium groups but in the absence of adscititious stabilizer or sulfonic substituent on the monomers is established first. Both the molecular weight and bulk electroconductivity of the copolymers exhibit a maximum at AQ content of 10 mol %. The solubility and film formability of the copolymers are good in highly polar solvents and reach the optimal at the AQ content of 20 and 10 mol %, respectively.