Corrosion-free electrochemical synthesis of polyaniline using Cu counter electrode in acidic medium

Progress in the Development of Intrinsically Conducting Polymer Composites as Biosensors

Biosensors are analytical devices which find extensive applications in fields such as the food industry, defense sector, environmental monitoring, and in clinical diagnosis. Similarly, intrinsically conducting polymers (ICPs) and their composites have lured immense interest in bio-sensing due to their various attributes like compatibility with biological molecules, efficient electron transfer upon biochemical reactions, loading of bio-reagent, and immobilization of biomolecules. Further, they are proficient in sensing diverse biological species and compounds like glucose (detection limit ≈0.18 nm), DNA (≈10 pm), cholesterol (≈1 µm), aptamer (≈0.8 pm), and also cancer cells (≈5 pm mL-1) making them a potential candidate for biological sensing functions. ICPs and their composites have been extensively exploited by researchers in the field of biosensors owing to these peculiarities; however, no consolidated literature on the usage of conducting polymer composites for biosensing functions is available. This review extensively elucidates on ICP composites and doped conjugated polymers for biosensing functions of copious biological species. In addition, a brief overview is provided on various forms of biosensors, their sensing mechanisms, and various methods of immobilizing biological species along with the life cycle assessment of biosensors for various biosensing applications, and their cost analysis.

Hybrid composite membranes of chitosan/sulfonated polyaniline/silica as polymer electrolyte membrane for fuel cells

A series of novel ionic cross-linked chitosan (CS) based hybrid nanocomposites were prepared by using polyaniline/nano silica (PAni/SiO₂) as inorganic filler and sulfuric acid as an ionic cross-linking agent. The CS-PAni/SiO₂ nanocomposites show enhanced mechanical properties and improved oxidative stabilities. These nanocomposites can be effectively used as environmental friendly proton exchange membranes. Incorporation of PAni/SiO₂ into CS matrix enhances water uptake and facilitates the phase separation which enables the formation of hydrophilic domains and improves the proton transport. Moreover, the doped polyaniline also provides some additional pathways for proton conduction. The membrane containing 3wt% loading of PAni/SiO₂ in chitosan (CS-PAni/SiO₂-3) exhibits high proton conductivity at 80°C (8.39×10^-3Scm^-1) in fully hydrated state due to its excellent water retention properties. Moreover, methanol permeability of the ionic cross-linked CS-PAni/SiO₂ nanocomposite membranes significantly reduces with the addition of PAni/SiO₂ nano particles. The CS-PAni/SiO₂-3 composite membrane displays the best overall performance as a polymer electrolyte membrane.