Polymer composites for energy storage and conversion

Since their discovery, conductive polymers have been studied extensively because of their fascinating physics and broad potential in technological applications. In this seminar, I will describe our use of doped conducting polymers as materials in energy-related technologies. Conductive polymers can be synthesized via chemical or electrochemical oxidation, producing a polycationic material that requires charge-compensating dopants. A variety of anionic dopants have been used including Cl-, ClO4-, BF4-, p-toluenesulfonate, dodecylbenzenesulfonate (DBS), and polystyrenesulfonate (pSS), all of which function to balance the cationic charge of the conductive polymer. More recently, our lab and others have introduced other dopants, which in addition to balancing the charge of the polymer, possess a distinct characteristic that imparts a new property or function to the composite. For example, proteins and peptide dopants impart bioactivity, whereas carbon nanotubes and hydrogen-bonding dopants enhance mechanical strength. Redox-active dopants improve electron transfer between the cathode of a biofuel cell to the active site of enzymes embedded in the conductive matrix, improve the energy density of batteries made from conductive polymers, yield a light-harvesting material, and add new colored states in electrochromic films. The performance of several devices made from conducting polymers will be presented

Lipoproteins and Diseases of the Brain

Apolipoprotein E4 (apoE4) and outer surface protein A (ospA) are pathogenic lipoproteins involved in the progression of Alzheimer’s disease and Lyme neuroborreliosis, respectively. Results from previous studies indicate that apoE4 exhibits neurotoxicity by activating amyloid beta pathways, and ospA causes damage to the brain by stimulating immune activity of microglia and astrocytes. These results, however, lack information about the specific interactions that develop between neurons and these two lipoproteins. It is essential to investigate the effect of these lipoproteins on neuronal morphology and function to better understand the mechanism of damage and disease of the brain. This chapter summarizes previous studies on the role of apoE4 and ospA in diseases of the brain and discusses experimental results from our own work that suggests new roles for apoE4 and ospA in neuronal outgrowth and synaptic loss

Voltammetric monitoring of laccase-catalysed mediated reactions

Six different compounds capable of mediating laccase-catalysed reactions have been tested by cyclic voltammetry. They exhibited quasi-reversible electrodic behaviour with formal redox potentials ranging from 150 to 800 mV (E-0t vs. SCE). The immersion of a laccase-coated glassy carbon electrode (GCE) in mediator solutions generated large cathodic catalytic currents easily recorded by cyclic voltammetry at low-potential scan rates. This current showed two well-defined pH profiles, which correlated with the variation of the mediator redox potentials at the pH range tested. The relevant effect of temperature on the activity of laccase has been assessed here. Likewise, it was shown that the cut-rent record varied with the substrate concentration. This trend fitted Michaelis-Menten kinetics, which allowed us to give an estimation of the affinity of the fungal laccase for the different mediators. (C) 2002 Elsevier Science B.V. All rights reserved

A Preliminary Study in Developing a Novel Vitamin D Biosensor Based on Electrochemical Detection

Abstract not Available.</jats:p

A New Cathode for Sodium Ion Batteries: Alluaudite Na_1.702Fe₃(PO₄)₃

Sodium-ion batteries hold promise as an enabling technology for large-scale energy storage that is safer, less expensive, and lower in terms of environmental impact than their equivalent lithium-ion batteries. In this presentation the synthesis, crystal structure, and electrochemical properties of a new sodium-ion battery cathode material, an alluaudite phase of Na1.702Fe3(PO4)3 will be described. After ball milling and carbon coating, this material exhibits a reversible capacity of 140.7 mAh/g with good cycling performance and excellent rate capability. In addition, we report a new compound in the alluaudite class, Na0.872Fe3(PO4)3, which was obtained upon desodiation of Na1.702Fe3(PO4)3. Both compounds exhibit high thermal stability. Together, these compounds represent a new cathode material for large-scale battery applications that are earth-abundant and sustainable.</jats:p

A scalable method for preparing Cu electrocatalysts that convert CO2 into C2+ products

Selective reduction of carbon dioxide to high-value products is key for advancing carbon capture and utilization technologies. Here the authors prepare a copper catalyst for electrocatalytic conversion of carbon dioxide to C2+ products with enhanced selectivity that is attributed to a high density of surface defects